Appendiceal neoplasms and pseudomyxoma peritonei: a population based study

The Pattern, Management, and Outcomes of Recurrence Following Cytoreductive Surgery for Pseudomyxoma Peritonei

BACKGROUNDS

We aimed to assess the pattern, management, and outcomes of recurrent pseudomyxoma peritonei (PMP) following cytoreductive surgery (CRS) and hyperthermic intraperitoneal chemotherapy (HIPEC) and compare repeat and index CRS/HIPEC.

METHODS

A retrospective review was performed of patients undergoing CRS/HIPEC for PMP between 01/01/2008 and 30/06/2022 at a tertiary referral center in New Zealand. Multivariate logistic regression was used to identify independent predictors of repeat CRS/HIPEC. Overall survival (OS) of PMP recurrence was stratified according to management strategy.

RESULTS

Among 183 primary CRS/HIPEC for appendiceal PMP, 154 (84.2%) achieved complete cytoreduction. Median follow-up duration was 72.1 months. Forty-nine recurred (31.8%). 40 (81.6%) cases of recurrence were isolated to the peritoneal cavity, and 47 (95.9%) occurred within 5 years. 27 (55.1%) underwent repeat curative-intent surgery. 22 (44.9%) were managed with palliative intent. Age > 65 and high-grade carcinoma peritonei (HG) were independent negative predictors of repeat curative-intent surgery. Five-year overall survival was significantly higher in patients undergoing repeat curative-intent surgery (80.3%) compared to those managed with palliative intent (44.8%) (HR = 0.23, p < 0.001). Curative-intent repeat surgery was an independent predictor of overall survival in PMP recurrences. Compared to primary CRS/HIPEC, repeat CRS/HIPEC were less extensive procedures conducted in cases with a lower peritoneal cancer index. Repeat CRS/HIPEC had similar peri-operative morbidity and long-term survival to primary procedures.

CONCLUSIONS

Repeat CRS/HIPEC for recurrent PMP is feasible and has similar safety and efficacy to index operations. Favorable long-term outcomes are achievable in well-selected patients.

Primary Lesions of the Appendix in Patients Undergoing Surgery for Gynecological Tumors

Appendiceal neoplasms are an incidental finding in <1% of all appendicectomy specimens. Their incidence rates are largely based on appendectomies performed for appendicitis. Appendicectomy is often performed as part of cytoreductive surgery for gynecological malignancies. This is to reduce the risk of occult metastatic disease and to mitigate the morbidity of acute appendicitis in patients undergoing chemotherapy for cancers. The objective of this study was to investigate the incidence of primary lesions of the appendix in 2 cohorts of patients who underwent appendicectomy: patients who had surgery for mucinous neoplasms of the ovary and patients who had cytoreductive surgery for gynecological malignancies. This study looked at the histopathology reports of 581 patients covering both cohorts. Appendicectomy in the setting of mucinous neoplasms of the ovary was done in 187 patients and as part of cytoreductive surgery for gynecological malignancies in 182 patients. We used the updated 2019 WHO nomenclature to classify the appendiceal lesions. The 2 cohorts had an incidence of 13% (25/187) and 7% (12/182) of appendiceal lesions. The appendix was noted to be the frequent primary site of extraovarian mucinous tumor metastasis to the ovary with a frequency of 56% (14/25) in patients with mucinous ovarian tumors; the highest cited in literature to date. We also noted poor correlation between gross and microscopic confirmation of appendiceal lesions with 7% of all macroscopically normal appendices harboring an appendiceal pathology. The study highlights the importance of appendicectomy during surgery for ovarian mucinous neoplasms and as part of cytoreductive surgery for gynecological malignancies. It also signifies the importance of microscopic examination of the whole appendix, especially when no gross abnormality is detected.

Pseudomyxoma peritonei originating from small intestine: A case report and review of literature

BACKGROUND

Pseudomyxoma peritonei (PMP) is a distinct form of peritoneal malignancy characterized by diffuse intra-abdominal gelatinous ascites, with an estimated incidence of 1-3 per 1000000. PMP is predominantly secondary to appendiceal mucinous neoplasms, with rarer origins including the ovaries, colon, and urachus. However, PMP originating from small intestine is extremely rare.

CASE SUMMARY

A 60-year-old male patient presented with anorexia and abdominal distension. Computed tomography revealed the presence of abdominopelvic effusions and multiple intra-abdominal space-occupying lesions. Ultrasound-guided aspiration indicated that the aspirated tissue was mucinous. Exploratory laparoscopy and tissue biopsy identified diffuse tumor nodules in peritoneum, omentum, pelvic region, intestinal walls, and mesentery. Histopathological analysis of the resected tumors confirmed the presence of mucinous adenocarcinoma, but the primary lesion was difficult to determine. The patient was referred to our center for further treatment and underwent cytoreductive surgery (CRS) combined with hyperthermic intraperitoneal chemotherapy (HIPEC) under general anesthesia. The intraoperative peritoneal cancer index was 30. The surgery lasted 8 hours, with a blood loss of about 600 mL. A complete cytoreduction (CCR0) was achieved. No serious complications occurred after surgery, and the patient's condition was good during the telephone follow-up. Postoperative pathology confirmed the diagnosis of small intestinal mucinous adenocarcinoma at proximal jejunum, which was complicated by high-grade PMP.

CONCLUSION

PMP originating from small intestine is an exceptionally rare entity that exhibits non-specific clinical features. The preferred treatment is CRS + HIPEC.

Laparoscopically resected appendiceal dual tumor composed of goblet cell carcinoma and low-grade mucinous neoplasm: a case report and literature review

Dual tumors, comprising two different types of tumor, are uncommon pathologic findings. Appendiceal goblet cell carcinoid is an unusual and unique subtype of primary appendiceal neuroendocrine tumor defined by the World Health Organization, showing hybrid epithelial-neuroendocrine features. Low-grade mucinous neoplasms are also rare appendiceal neoplasms. However, the relationship between these two types of tumors is not well known. We present the case of a 46-year-old woman with a 5 cm appendiceal cystic tumor that was incidentally detected on abdominal computed tomography. She showed no abdominal symptoms, enlarged lymph nodes, or obvious distant metastases. Laparoscopic ileocecal resection was performed without complications or tumor injury. No disseminated lesions or mucus accumulation was found in the abdominal cavity during the operation. Pathologic examination revealed low-grade mucinous tumor cells lining the cystic mucosal cavity and a chromogranin A-positive goblet cell carcinoid near the mucinous cell components. As there was no mixture of the two cell types, the tumor was suspected of a collision tumor. Although reports on appendiceal collision tumors are limited, these two tumor types might arise from different types of progenitor cells. Furthermore, the laparoscopic approach, which allows for a more detailed and safer observation of the entire abdominal cavity, could be useful for accurate staging and treatment decisions in mucinous appendiceal tumors at risk of intraperitoneal mucinous dissemination and peritoneal pseudomyxoma. Accumulation of case reports of such dual tumors and analysis at the molecular and cellular level are necessary to elucidate their pathogenesis and development.

Evaluation of prenatal and postnatal outcomes of fetuses with intrauterine cardiac anomalies: Tertiary center experience

Objective

Fetal cardiac anomalies are among the leading causes of infant mortality due to congenital anomalies. The prenatal diagnosis of congenital heart diseases allows for the acquisition of prognostic information before birth and provides insights into treatment options either before or after delivery. This study aims to observe the correlation between the prenatal and postnatal diagnoses of fetuses with cardiac anomalies detected in our perinatology clinic. The goal, by tracking postnatal outcomes and identifying risk factors, is to assist in selecting the most appropriate approach, prioritizing maternal and fetal health.

Materials and Methods

The records of 188 fetuses diagnosed during the prenatal period by the Perinatology Department of Obstetrics and Gynecology at Çukurova University Faculty of Medicine, delivered and admitted to the Çukurova University Neonatal Intensive Care Unit, and undergoing fetal echocardiography by the Pediatric Cardiology Clinic between January 2016 and December 2021, were retrospectively evaluated. Postnatal transthoracic echocardiography results of the infants were also reviewed.

Results

Our study was conducted with 188 pregnant women. The most frequently detected cardiac anomalies in the fetuses were conotruncal anomalies, followed by right heart anomalies. The concordance between prenatal and postnatal findings was 88.8%, with a sensitivity of 96.55% and a specificity of 100%. Among the live-born infants with congenital heart disease, significant differences were observed between the group that survived the neonatal period and those who did not, in terms of parental consanguinity, gestational age at birth, birth weight, APGAR scores, and the rate of chromosomal anomaly assessment.

Conclusion

Our study emphasized several risk factors. A high concordance was found between our prenatal and postnatal echocardiography findings. In conclusion, we believe that increasing awareness and making screening a routine practice are essential to contributing to healthier future generations. This can be achieved by reducing perinatal mortality and morbidity through appropriate management and equipment, thereby optimizing the well-being of affected individuals in society.

Mucinous adenocarcinoma of the appendix invading in the sigmoid colon: Case report

INTRODUCTION

Mucinous appendiceal adenocarcinoma (MAA) is a rare malignancy that can occasionally present with complications such as rupture and local invasion. This report details a unique case of MAA rupturing into the sigmoid colon and the subsequent management of the patient.

CASE PRESENTATION

A 62-year-old male presented with hypogastric abdominal pain, diarrhea, fever, and a palpable abdominal mass. A CT scan revealed an 8 cm intraperitoneal collection in contact with both the appendix and the sigmoid colon, suggesting acute appendicitis complicated by an abscess. An emergency laparotomy was performed, revealing an abscess involving both organs. An en-bloc resection of the appendix and the sigmoid colon was performed, followed by a Hartmann procedure. Histopathological analysis confirmed mucinous cystadenocarcinoma of the appendix invading the sigmoid colon, with clear resection margins and no lymph node involvement (pT4b). After a normal postoperative CT scan and colonoscopy, the patient underwent a right hemicolectomy and restoration of digestive continuity, with no residual tumor found.

DISCUSSION

MAA is an uncommon malignancy, and its rupture into the sigmoid colon is exceedingly rare. This case highlights the importance of prompt surgical intervention in managing complications such as abscess formation and tumor invasion. The en-bloc resection and Hartmann procedure were effective in removing the diseased tissues, and subsequent follow-up with right hemicolectomy confirmed no further tumor spread.

CONCLUSION

This case demonstrates the successful management of mucinous appendiceal adenocarcinoma rupturing into the sigmoid colon through timely surgical intervention. This case underscores the importance of early diagnosis and aggressive treatment in achieving positive outcomes for rare malignancies.

Prognosis conferred by molecular features of appendix-derived Pseudomyxoma Peritonei

INTRODUCTION

Pseudomyxoma Peritonei (PMP) is an extremely rare disease characterized by progressive accumulation of mucinous ascites and implants in the peritoneum. We investigated the prognostic value for response to cytoreductive surgery (CRS) or hyperthermic intraperitoneal chemotherapy (HIPEC) and dissected potential beneficial targeted therapy utilizing genomic characteristics.

METHODS

Whole-exome sequencing (WES) was performed on tissue specimens and matched white blood cells from 81 patients with PMP. The study investigated mutational signatures, profiling, and their correlation with progression-free survival (PFS) and overall survival (OS).

RESULTS

Signature 3 (HRD) and signature 15 (dMMR) were dominant. NMF cluster 1, characterized by signature 4, exhibited a worse prognosis. The p53 and TGF-β signaling pathways may contribute as risk factors for worse OS and PFS, respectively. MUC16-mutated patients had worse PFS (P = 0.016) and OS (P = 0.004) compared to wild-type patients. Patients with tumor mutational burden (TMB) > 1(P = 0.026) or alterations in TP53 (P = 0.006) or SMAD4 (P = 0.013) had significantly worse OS compared to those with a TMB < 1 or normal genes. Patients with homologous recombination deficiency (HRD) positivity (P = 0.003) or alterations in TGFBR2 (P = 0.037) experienced worse PFS compared to their respective control groups. Furthermore, NMF cluster1 (P = 0.020), TP53 (P = 0.004), and MUC16 (P = 0.013) were identified as independent prognostic factors for OS, while HRD status (P = 0.003) was independent predictors for PFS in PMP.

CONCLUSIONS

The study reveals that genomic profiling can serve as a robust tool for identifying prognostic markers in PMP. The identified genomic mutations and signaling pathway offer new avenues for targeted therapies.

Total parietal peritonectomy and multivisceral resection for extensive cytoreductive surgery in pseudomyxoma peritonei: En bloc "Rolled-up carpet" technique and perioperative and oncologic outcomes

BACKGROUND

Patients diagnosed with pseudomyxoma peritonei (PMP) of appendiceal origin typically present with high tumor burden and require extensive cytoreductive surgery (CRS) to achieve optimal cytoreduction. This study describes an en bloc "rolled-up carpet" surgical technique for total parietal peritonectomy and multivisceral resection while also analyzing the perioperative and tumor outcomes of this technique.

METHODS

The study reviewed the data of 7 patients underwent en bloc "rolled-up carpet" extensive CRS between August 2020 and April 2023. Perioperative and tumor outcomes were analyzed.

RESULTS

Seven patients underwent extensive treatment involving total peritoneal and multivisceral resection. Complete cytoreduction was successfully achieved in all patients. Six patients (85.7 %) successfully completed hyperthermic intraperitoneal chemotherapy (HIPEC). Three patients (42.9 %) had low-grade mucinous appendiceal neoplasm, while the remaining four patients (57.1 %) had high-grade. Two patients (28.6 %) experienced major morbidity, which was successfully treated, and they were discharged. There were no secondary surgery and no surgery-related mortality. During a median follow-up of 25 months (range, 12-46 months), no patient experienced recurrence. After 12 months postoperatively, the quality of life (QOL) of the 7 patients was assessed using the EORTC QLQ-C30, revealing scores similar to the reference values of the EORTC general population (p > 0.05).

CONCLUSION

En bloc "rolled-up carpet" extensive cytoreductive surgery is a feasible and safe technique for the treatment of appendiceal PMP with high tumor burden. This technique achieved complete cytoreduction with acceptable blood loss volume, operative time, and major morbidity. In short-term follow-up, no recurrence was noted, with patients having a satisfactory QOL.

Predictors of Recurrence in Nonmetastatic Appendiceal Epithelial Cancers: An Updated Single-Center Experience Over 25 Years

BACKGROUND

Appendiceal epithelial tumors are rare and encompass a broad set of adenocarcinoma histologies, including mucinous (mAC), colonic-type (cAC), and goblet cell (GCA) adenocarcinomas. It has previously been reported that nodal disease predicted recurrence in patients with nonmetastatic appendiceal adenocarcinomas, supporting diagnostic laparoscopy with right hemicolectomy for staging and assessment for risk of recurrence. In this update, we sought to identify predictors of nodal disease on initial diagnostic pathology in nonmetastatic adenocarcinomas.

METHODS

Patients with nonmetastatic appendiceal adenocarcinoma at a single institution from 1994 to 2020 were included. Clinicopathologic characteristics that predict recurrence and lymph node metastasis were analyzed. Workup included staging laparoscopy with right hemicolectomy, seriel imaging and biochemical monitoring.

RESULTS

A total of 147 patients with mAC (18%), cAC (22%), and GCAs (59%) were included. After median follow-up of 53 months, 23 (16%) patients recurred, most commonly in the peritoneal cavity (17/23, 74%). Recurrence rates were higher among node-positive patients (59% vs. 5%, P < 0.001). Nodal disease was more common in mAC (27%) and cAC (37%) than in GCA (11%); however, adenocarcinoma grade was not associated with nodal involvement.

CONCLUSIONS

Nodal metastasis was more common in mAC and cAC compared with GCA and was the only significant predictor of recurrence in appendix cancer.

Cell of origin and expression profiles of pseudomyxoma peritonei derived from the appendix

Pseudomyxoma peritonei (PMP) is a rare disease caused by mucin-producing tumors that develop most frequently from the appendix. The disease is characterized by the accumulation of mucin in the abdominal cavity. Although frequent mutations in the KRAS and GNAS genes have been reported in PMP, gene expression profiles of the tumors remain to be fully clarified because of its rarity and the difficulties in collecting pure cancerous cells scattered within the mucin. To disclose the molecular features of PMP cells, we performed RNA-seq analysis of ten PMPs and their matched non-tumorous colonic epithelium in combination with laser-microdissection. As a result, we identified a total of 32 differently expressed genes (DEGs) between the tumors and non-tumorous colonic epithelium. A cell-of-origin subtype analysis with the nearest template prediction algorithm corroborated that PMP tumor cells belonged to the goblet cell subtype, and tumorous cells of PMP appear to arise from goblet cells. Interestingly, over representation analysis (ORA) uncovered that the tumors were significantly associated with three ontology terms, namely epithelial mesenchymal transition (EMT), angiogenesis, and inflammatory response. Comparison of gene expression profiles between disseminated peritoneal adenomucinosis (DPAM) and peritoneal mucinous adenocarcinomas (PMCA) identified a total of 687 DEGs. Additional gene set enrichment analysis (GSEA) revealed that ontology terms "G2M checkpoint" and "E2F targets" were significantly enriched in PMCA supporting the view that PMCA has more aggressive properties than DPAM. These data may be useful to further understand the molecular characteristics of PMP.

Pseudomyxoma Peritonei: A Case Report of a Patient With Unexplained Granulomas

Pseudomyxoma peritonei is a rare type of neoplasm, characterized by the presence of mucinous tumors on the peritoneal surface. The authors report the case of a 79-year-old male who came to the hospital with abdominal pain and distension, weight loss, and increased abdominal perimeter. Histopathology is fundamental for making the diagnosis. Survival depends on the extent of the neoplasm. This case reveals the challenges of reaching an accurate and prompt diagnosis of pseudomyxoma peritonei.

Negative Impact of Systemic Therapy on Survival in Patients Undergoing Cytoreductive Surgery and Hyperthermic Intraperitoneal Chemotherapy for Low-Grade Metastatic Appendiceal Adenocarcinoma

BACKGROUND

Despite studies demonstrating that patients with peritoneal metastases from low-grade appendiceal adenocarcinoma (AA) do not respond well to systemic chemotherapy (SC), patients frequently undergo combination of SC with cytoreductive surgery/hyperthermic intraperitoneal chemotherapy (CRS/HIPEC) regardless of grade.

METHODS

A nationwide retrospective analysis using the National Cancer Database evaluated patients with AA with peritoneal metastasis from 2016 to 2021. Cox proportional hazards model was used to evaluate the impact of SC in addition to CRS/HIPEC on overall survival (OS) stratified by tumor grade.

RESULTS

A total of 1,449 patients were included: 481 low-grade, 428 intermediate-grade, and 540 high-grade tumors. Clinical variables, such as age, sex, and comorbidity index, were similar across tumor grades. Cytoreductive surgery/hyperthermic intraperitoneal chemotherapy without SC was utilized in 65.73% of low-grade cases compared with 41.01% in intermediate-grade and 11.11% in high-grade cases. Systemic chemotherapy was utilized alone in 17.74% and with CRS/HIPEC in 16.53% of low-grade cases. In adjusted survival analysis, addition of SC to CRS/HIPEC was associated with worse OS for patients with low-grade AA (hazard ratio [HR] 2.77, 95% confidence interval [CI] 1.18-6.50) but not for intermediate (HR 1.65, 95% CI 0.82-3.35) and high-grade tumors (HR 1.18, 95% CI 0.67-2.45). The addition of time to definitive surgery variable nullified the negative impact of adding SC to CRS/HIPEC in low-grade AA (HR 1.76, 95% CI 0.68-4.53).

CONCLUSIONS

Negative OS impact of SC may be mediated by delays in effective surgical/intraoperative therapy. If CRS/HIPEC is planned for patients with metastatic low-grade AA, avoiding SC may facilitate earlier surgical intervention and improve survival.

Prediction of preoperative peritoneal cancer index for pseudomyxoma peritonei by multiple linear regression analysis

Background

The aim of the present study was to establish a predictive model to predict the peritoneal cancer index (PCI) preoperatively in patients with pseudomyxoma peritonei (PMP).

Methods

A total of 372 PMP patients were consecutively included from a prospective follow-up database between 1 June 2013 and 1 June 2023. Nine potential variables, namely, gender, age, Barthel Index (BAI), hemoglobin (Hb), albumin (Alb), D-dimer, carcinoembryonic antigen (CEA), carbohydrate antigen 125 (CA 125), and CA 19-9, were estimated using multiple linear regression (MLR) analysis with a stepwise selection procedure. The established MLR model was internally validated using K-fold cross-validation. The agreement between the predicted and surgical PCI was assessed using Bland–Altman plots and intraclass correlation (ICC). A p-value of less than 0.05 was considered statistically significant.

Results

Six independent predictors were confirmed by the stepwise MLR analysis with an R2 value of 0.570. The predicted PCI formula was represented as follows: PCI = 19.567 + 2.091 * Gender (male = 1, female = 0) − 0.643 * Alb +4.201 * Lg (D-dimer) + 2.938 * Lg (CEA) + 5.441 * Lg (CA 125) + 1.802 * Lg (CA 19-9). The agreement between predicted and surgical PCI was assessed using Bland–Altman plots, showing a limit of agreement (LoA) between −15.847 (95%CI: −17.2646 to −14.4292) and +15.847 (95%CI: 14.4292–17.2646).

Conclusion

This study represents the first attempt to use an MLR model for the preoperative prediction of PCI in PMP patients. Nevertheless, the MLR model did not perform well enough in predicting preoperative PCI. In the future, more advanced statistical techniques and a radiomics-based CT-PCI-participated MLR model will be developed, which may enhance the predictive ability of PCI.

Laparoscopic cecal pole resection for LAMN a case report

INTRODUCTION AND IMPORTANCE

Low-grade appendicular mucinous neoplasms are rare. In contrast to other malignant tumors, they lack the ability for infiltrative growth or lymph node metastasis, but intraperitoneal mucin spread may lead to a life-threatening condition, known as a pseudomyxoma peritonei.

CASE PRESENTATION

Patient, a 47-year-old female, with complaints of a palpable mass in her right inguinal area, presented to our clinic. After a clinical workup, which included computer tomography, magnetic resonance imaging, and colonoscopy, a preliminary diagnosis of LAMN was established. Laparoscopic cecal pole resection was performed. A pathological examination confirmed the diagnosis of LAMN. Patient was followed up for six months after the surgery, at which point a contrast-enhanced CT scan was obtained with no pathological findings.

CLINICAL DISCUSSION

Mucinous neoplasms of the appendix are a group of tumors in which mucin accumulates within the lumen of the appendix and while this type of neoplasia cannot spread hematologically, extramural mucin may lead to pseudomyxoma peritonei. Not long ago, a right hemicolectomy was accepted as a radical treatment method. Nowadays various studies have shown that laparoscopic appendectomy may be a safe option in patients with mucin, confined to the lumen of the appendix. This case holds educational value due to the detailed course of the disease presented and justified clinical decisions.

CONCLUSION

LAMN is a rare type of neoplasm. When confined to the lumen of the appendix, it lacks the ability for infiltrative growth and lymph node metastasis. Appropriate treatment in case of a contained disease is surgical removal.

Pseudomyxoma peritonei of appendiceal mucinous neoplasm origin: A case report and review of literature

Appendiceal mucinous neoplasms, a rarity comprising less than 1% of all cancers, present intricate challenges in clinical management, and their incidence is on the rise. Notably, these neoplasms tend to metastasize intraperitoneally, leading to peritoneal carcinomatosis and concurrent accumulation of mucinous material, resulting in pseudomyxoma peritonei. Due to its spectrum of presentation, the classification of the appendiceal mucinous neoplasms remains a controversial subject with a range of management from a simple appendicectomy to a complex hyperthermic intraperitoneal chemotherapy (HIPEC). A 42-year-old Chadian male presented to the hospital with a sudden onset of right lower abdominal pain radiating to the inguinal region for 24 hours, associated with nausea and vomiting. The abdomen was distended and ascitic. Laboratory investigations revealed anemia, leukocytosis, hypernatremia, hypokalemia, elevated ESR, high CEA marker, and normal CA19-9. An abdominopelvic CT with contrast demonstrated extensive ascites and cystic masses in the liver, and pancreas with soft tissue thickening of the cecum; however, the appendix is not well-delineated. Patient was managed with chemotherapy and HIPEC followed by removal of all the affected parts. Nodules of the peritoneum and liver were submitted for histopathological analysis and a final diagnosis of pseudomyxoma peritonei of primary appendicular origin was established. This case highlights a case of extensive pseudomyxoma peritonei of appendicular origin managed aggressively by HIPEC and multiple resections of the involved organs. Prognosis of such a case is determined by the grade of the appendiceal tumor and the extent of invasion.

Reclassification of Appendiceal Mucinous Neoplasms and Associated Pseudomyxoma Peritonei According to the Peritoneal Surface Oncology Group International Consensus: Clinicopathological Reflections of a Two-Center Cohort Study

BACKGROUND

International consensus on classifications of appendiceal mucinous neoplasms (AMNs) and associated pseudomyxoma peritonei (PMP) have been carefully made but clinicopathological associations supporting decision making remain scarce.

OBJECTIVE

This study aimed to assess interdependence between AMNs and PMP and provide directions for clinical management.

METHODS

This two-center retrospective cohort study reviewed patients with PMP treated with cytoreductive surgery and hyperthermic intraperitoneal chemotherapy between 2005 and 2021. The primary objective was to reassess histopathologic grade of AMNs and PMP according to the Peritoneal Surface Oncology Group International classification and to establish its interdependence. Secondary outcomes were recurrence rate, PMP grade progression, ovarian involvement, and overall survival (OS).

RESULTS

Of 105 patients included, 78 (74.3%) had low-grade AMNs as the primary tumor, 8 (7.6%) had high-grade AMNs, 7 (6.7%) had mucinous adenocarcinoma (MAC), 1 (0.9%) had MAC with signet ring cells (SRC), and 11 (10.5%) had unidentified tumors. Overall, 11 patients (10.5%) had no PMP, 21 (20.0%) had acellular mucin, 56 (53.3%) had low-grade PMP, 12 (11.4%) had high-grade PMP, and 5 (4.8%) had PMP-SRC. In 11 cases (13.3%), AMNs and matching PMP grade differed. Over a 16-year follow-up, recurrence occurred in 31.8%, with three cases showing histopathologically changed PMP. Ovarian involvement was observed in 43/65 females (66.2%). Median OS was 13.8 years, and 5-year OS rates were 100%, 74.4%, 44.4%, and 20% for acellular mucin, low-grade PMP, high-grade PMP and PMP-SRC, respectively (p < 0.001).

CONCLUSIONS

AMN histology does not always reflects its associated PMP grade, while PMP grade strongly influences survival. Ovarian involvement and recurrent PMP showing unchanged histopathological features are common.

Prophylactic cytoreductive surgery and hyperthermic intraperitoneal chemotherapy for low-grade appendiceal mucinous tumors with early and limited disease after completely removed

The necessity of prophylactic cytoreductive surgery (PCRS) and hyperthermic intraperitoneal chemotherapy (HIPEC) for low-grade appendiceal mucinous neoplasms (LAMN) after complete removal is still controversial. This study aims to determine the role of PCRS + HIPEC and identify optimal strategies for managing these patients. One hundred fifty-nine patients who sought medical advice at Aerospace Center Hospital were retrospectively analyzed from January 2011 to December 2021. All the patients were divided into the PCRS group and the observation group. The data of surgical specimens and pathology was collected, and the effect on recurrence-free survival (RFS) was analyzed. Of these 159 patients, 88 were in the PCRS group, and 71 were in the observation group. The median follow-up time was 38 months. Seven patients recurred and developed into pseudomyxoma peritonei, 1 in the PCRS group and 6 in the observation group. The analysis of RFS showed that patients who underwent PCRS (P = .01) and HIPEC (P = .01) had better survival. After multivariate analysis, the surgical specimen accompanied by disseminated peritoneal adenocarcinoma was identified as an independent prognostic factor for RFS. In the study of surgical resection content, patients with greater omentum (P = .01) and bilateral fallopian tubes and ovaries of women (P = .002) resection had a more prolonged RFS with statistical significance. The research indicated that PCRS + HIPEC could prevent recurrence. Therefore this treatment were necessary for LAMN after complete removal in patients with a high risk of recurrence. However, it was not proven to be an independent factor for RFS, and a multicenter, prospective, randomized trial was need to definitively address the role of PCRS + HIPEC for LAMN after complete resection.

Molecular and Clinicopathologic Impact of GNAS Variants Across Solid Tumors

PURPOSE

The molecular drivers underlying mucinous tumor pathogenicity are poorly understood. GNAS mutations predict metastatic burden and treatment resistance in mucinous appendiceal adenocarcinoma. We investigated the pan-cancer clinicopathologic relevance of GNAS variants.

METHODS

We assessed 58,043 patients with Memorial Sloan Kettering-Integrated Mutation Profiling of Actionable Cancer Targets (IMPACT)-sequenced solid tumors to identify oncogenic variants, including GNAS, associated with mucinous tumor phenotype. We then performed comprehensive molecular analyses to compare GNAS-mutant (mut) and wild-type tumors across cancers. Gene expression patterns associated with GNAS-mut tumors were assessed in a The Cancer Genome Atlas cohort. Associations between GNAS variant status and peritoneal metastasis, first-line systemic therapy response, progression-free survival (PFS), and overall survival (OS) were determined using a propensity-matched subcohort of patients with metastatic disease.

RESULTS

Mucinous tumors were enriched for oncogenic GNAS variants. GNAS was mutated in >1% of small bowel, cervical, colorectal, pancreatic, esophagogastric, hepatobiliary, and GI neuroendocrine cancers. Across these cancers, GNAS-mut tumors exhibited a generally conserved C-to-T mutation-high, aneuploidy-low molecular profile with co-occurring prevalent KRAS variants (65% of GNAS-mut tumors) and fewer TP53 alterations. GNAS-mut tumors exhibited recurrently comutated alternative tumor suppressors (RBM10, INPPL1) and upregulation of MAPK and cell surface modulators. GNAS-mut tumors demonstrate an increased prevalence of peritoneal metastases (odds ratio [OR], 1.7 [95% CI, 1.1 to 2.5]; P = .006), worse response to first-line systemic therapy (OR, 2.2 [95% CI, 1.3 to 3.8]; P = .003), and shorter PFS (median, 5.6 v 7.0 months; P = .047). In a multivariable analysis, GNAS mutated status was independently prognostic of worse OS (hazard ratio, 1.25 [95% CI, 1.01 to 1.56]; adjusted P = .04).

CONCLUSION

Across the assessed cancers, GNAS-mut tumors exhibit a conserved molecular and clinical phenotype defined by mucinous tumor status, increased peritoneal metastasis, poor response to first-line systemic therapy, and worse survival.

A combinatorial culture strategy to develop pseudomyxoma peritonei organoid models

BACKGROUND AND OBJECTIVES

Few preclinical models of pseudomyxoma peritonei (PMP) have been developed, probably due to the tumor's low incidence and its peculiar characteristics of slow growth. Therefore, there is a need to develop more refined PMP models that better reflect its characteristics. The aim of the study is to develop a culture strategy to generate organoid models derived from PMP patient samples.

METHODS

We followed a strategy based on combinatorial culture conditions that include the different factors essential for PMP growth and that mimic the microenvironment present in the patients.

RESULTS

We cultured PMP samples in the presence of the various factors produced by the niche environment of PMP. We obtained 12 PMP organoid models, each of which grows under specific culture conditions. PMP-derived organoids show long-term expansion capacity and reproduce the genetic landscape and histological phenotype of the tumor of origin.

CONCLUSION

The organoids we developed faithfully reproduce the key features of PMP disease and will allow us to understand the biology of PMP. With them, we will be able to identify key regulatory networks that support PMP progression, providing a platform for multilevel preclinical testing, identify novel diagnostic biomarkers, and generate novel targets for patient treatments.

New insights in the management of pseudomyxoma peritonei

While a rare entity, peritoneal pseudomyxoma treatment evolves. Decision-making criteria improve with imaging development and exploratory laparoscopy. Surgery remains at the core of the therapeutic strategy whatever disease progression. Complete cytoreduction plus hyperthermic intraperitoneal chemotherapy (HIPEC) is standard of care. Iterative cytoreduction or debulking is sometimes justified. Intraperitoneal chemotherapy modalities change with early postoperative HIPEC or pressurized intraperitoneal aerosol chemotherapy. Systemic or local treatment such as new chemo/immuno-therapies or BromAc should improve outcomes. Expertise and multicentric cooperation are more than ever needed.

The risk of developing pseudomyxoma peritonei from a non-perforated low grade appendiceal mucinous neoplasm found at appendicectomy

INTRODUCTION

Low-grade appendiceal mucinous neoplasms (LAMNs) are classified as non-perforated (pTis, pT3) or perforated (pT4), and considered precursors of pseudomyxoma peritonei (PMP). This study aims to quantify the risk of developing PMP from pTis and pT3 LAMNs.

MATERIALS AND METHODS

Retrospective analysis of a prospectively collected database identified LAMN patients referred to a specialist centre from 2004 to 2019. pT4 LAMNs and other appendix tumours were excluded. All patients had specialist review of their pathology, operation note, and a CT scan (at least 6 weeks post-operatively). Surveillance CTs were then performed at 6, 12, 24, 36, 48, & 60 months, with tumour markers (CEA, CA19-9, CA125).

RESULTS

193 pT3/pTis LAMN patients were included (pTis = 153, pT3 = 40). Median follow-up = 6.45 (3.91-22.13) years, M:F ratio = 1:1.57, and median age = 57 (23-83) years. Initial surgery included: appendicectomy (67 %), appendicectomy + visceral resection (6 %), and right hemicolectomy (27 %). R1 resections were identified in 5/193 patients (2.5 %). 3 R1 patients underwent re-operation (2 caecal pole excision and 1 ileocecectomy), none of which had residual tumour. 8/193 patients (4 %) were lost to follow up. None of the remaining 185 developed PMP.

CONCLUSION

This is the largest reported series of pTis/pT3 LAMNs with standardised follow-up in the literature. LAMNs correctly classified as pT3/pTis (after careful specialist review of pathology, operation note, and a baseline post-operative CT) have negligible risk of developing PMP and should have low intensity surveillance. If completely excised, further surgery is not indicated. R1 resections should be considered on an individual basis at a specialist centre.

Targeted Genetic Sequencing Analysis of 223 Cases of Pseudomyxoma Peritonei Treated by Cytoreductive Surgery and Hyperthermic Intraperitoneal Chemotherapy Shows Survival Related to GNAS and KRAS Status

BACKGROUND AND AIM

Pseudomyxoma peritonei (PMP) is an unusual condition with unique behaviour caused by a mucinous neoplasm, usually arising from the appendix. The aim of this study was to evaluate the prevalence of genomic alterations in clinical specimens of PMP using a targeted assay and correlate the findings with clinical, pathological and outcome data. Sequencing data from 223 patients were analysed.

RESULTS

The median follow-up interval was 48 months. The primary neoplasm was appendiceal in 216 patients, ovarian in 4, urachal in 2 and renal in one. We confirmed common mutations in GNAS and KRAS (42% each) with significant co-occurrence of variants in these genes. TP53 mutations were found in 8%. Other mutations were rare but included novel mutations in BAP1 and ERBB4. Of 17 patients with acellular peritoneal mucin, 6 (35%) were positive for DNA mutations. The non-appendiceal cases generally showed a similar mutational landscape to the appendiceal lesions with GNAS and KRAS commonly mutated, although one urachal lesion showed multi-hit TP53 mutation without variants in either GNAS or KRAS. Survival was significantly associated with the grade of the primary neoplasm, the grade of the peritoneal disease, the completeness of cytoreduction score and with mutation in either GNAS, KRAS or both. The hazard ratio (HR) associated with mutation in GNAS and/or KRAS was 1.87 (p = 0.004).

CONCLUSIONS

Survival outcome was more closely associated with the grade of the peritoneal disease than with the grade of the primary neoplasm. Our findings support the developing concept that mutational analysis may provide prognostic information in patients with PMP.

Appendiceal adenocarcinoma: Current concepts & challenges

Appendiceal adenocarcinoma (ApAC) is a rare malignancy, comprising less than 1 % of all gastrointestinal tumors. The current World Health Organization classifies ApAC as mucinous or nonmucinous. Mucinous ApAC are composed of pools of mucin lined by cells with low- and high-grade cytology and areas of infiltrative invasion. Nonmucinous ApAC histologically resemble conventional colorectal adenocarcinomas and have a worse prognosis than their mucinous counterpart. Unfortunately, the nomenclature and histologic classification of ApAC, specifically the mucinous subtype, has changed several times throughout the years, contributing to diagnostic confusion for pathologists. The treatment for mucinous ApAC differs from that of other appendiceal mucinous neoplasms, thus accurate diagnosis is key to patient management and outcome. This review discusses the current classification and staging of ApAC with a particular emphasis on the mucinous subtype and peritoneal disease, as these areas are the most challenging for practicing surgical pathologists.

Exploring the mysterious mucinous appendiceal neoplasm

Mucinous neoplasms of the appendix comprise a group of diagnostically challenging lesions that have generated significant controversy and confusion throughout the years, given their potential for aggressive behavior despite very bland cytologic features. Numerous classification schemes have been proposed to characterize and stage these lesions, but confusion remains among pathologists, surgeons, and oncologists regarding diagnostic criteria, therapeutic implications, and overall prognosis. This review summaries the current recommended nomenclature, histologic characteristics of each entity, and helpful features to distinguish neoplasia from benign mimics.

Recurrence and metastasis of pseudomyxoma peritonei: A rare case report

Pseudomyxoma peritonei (PMP) is a relatively uncommon condition primarily associated with neoplasms of the appendiceal epithelium. It is characterized by non-specific clinical manifestations, leading to a high rate of misdiagnosis. This report describes the case of a 62-year-old male patient with recurrent and metastatic PMP. The patient first experienced unexplained epigastric pain and paroxysmal abdominal pain accompanied by distension over 8 years ago. He underwent surgical interventions for the condition in other hospitals in 2015 and 2018, respectively.

Pseudomyxoma Peritonei in a Case of Carcinoma Cervix: Subtle Finding With Implications on Management and Prognosis

Pseudomyxoma peritonei (PMP) is a well-known entity in gastrointestinal and ovarian tumors of mucinous histology. It has important implications on prognosis depending on whether seen in conjunction with a benign or a malignant tumor. In the current report, we describe a case of PMP in a case of advanced endocervical adenocarcinoma of the cervix which was managed surgically.

What is the optimum post treatment surveillance imaging protocol for low-grade appendiceal mucinous neoplasms and pseudomyxoma peritoneii?

Appendiceal mucinous neoplasms are rare and can be associated with the development of disseminated peritoneal disease known as pseudomyxoma peritonei (PMP). Mucinous tumours identified on appendicectomy are therefore followed up to assess for recurrence and the development of PMP. In addition, individuals who initially present with PMP and are treated with cytoreductive surgery and hyperthermic intraperitoneal chemotherapy (CRS/HIPEC) are followed up to assess for recurrence. However, despite the concerted efforts of multiple expert groups, the optimal imaging follow-up protocol is yet to be established. The purpose of this article is to review the available evidence for imaging surveillance in these populations to identify the optimum post-resection imaging follow-up protocol.

LAMN port-site metastasis after laparoscopic oophorectomy for a presumed ovarian tumour treated with CRS and HIPEC

Low-grade appendiceal mucinous neoplasm (LAMN) may culminate as a mucin-secreting disease known as pseudomyxoma peritonei (PMP). Once the diagnosis of LAMN and PMP is made, cytoreductive surgery and hyperthermic intraperitoneal chemotherapy (CRS and HIPEC) are indicated.Herein, we present a female patient in her 50s who was diagnosed with an ovarian mass for which she underwent laparoscopic oophorectomy. As the pathology of the ovary showed a tumour of gastrointestinal origin, she then underwent CRS and HIPEC with a final pathology of LAMN. Six weeks later, a mucinous lesion confined to the abdominal wall was detected on a postoperative CT. Suspected for port-site metastasis at the laparoscopic trocar site, we treated this lesion using the same principles of treatment as the intra-abdominal disease. The abdominal wall mass was surgically resected, and the cavity created was irrigated with mitomycin C. On 30 months of follow-up, the patient had no evidence of disease.

Visualizing the landscape of appendiceal tumor research after 2010: A bibliometric study

BACKGROUND

Despite the rarity of appendiceal tumors, research in this field has intensified, resulting in a growing number of studies and published papers. Surprisingly, no comprehensive bibliometric analysis has specifically addressed appendiceal tumors.

AIM

To offer a thorough analysis of the current landscape and future trends in appendiceal tumor research.

METHODS

In our bibliometric analysis studies, we explored the Web of Science Core Collection database. The bibliographic details of the chosen publications were automatically converted and analyzed using the bibliometric package in the R environment. Additionally, we employed VoSviewer to create cooperation network maps for countries, institutions, and authors, as well as clustering maps for keywords. Furthermore, CiteSpace, another software tool, was utilized to build dual-map overlays of journals and analyze references with citation bursts.

RESULTS

Our study included 780 English-language articles published after 2010. The number of related publications and citations has increased in the past decade. The United States leads in this area, but there is a need to improve cooperation and communication among countries and institutions. Co-occurrence analysis also revealed close collaboration among different authors. Annals of Surgical Oncology was the most influential journal in this field. Analysis of references with high co-citations and references with citation bursts, consistent with analysis of keywords and hotspots, indicated that current research primarily centers on the classification and management of appendiceal mucinous neoplasms and consequent pseudomyxoma peritonei. Despite the abundance of clinical studies, a greater number of in-depth basic research studies should be conducted.

CONCLUSION

Current research on appendiceal tumors focuses on classification and management of appendiceal mucinous neoplasms and pseudomyxoma peritonei. Enhanced collaboration and basic research are vital for further advancement.

Breaking the Mucin Barrier: A New Affinity Chromatography-Mass Spectrometry Approach to Unveil Potential Cell Markers and Pathways Altered in Pseudomyxoma Peritonei

BACKGROUND

Pseudomyxoma peritonei (PMP) is a rare peritoneal mucinous carcinomatosis with largely unknown underlying molecular mechanisms. Cytoreductive surgery combined with hyperthermic intraperitoneal chemotherapy is the only therapeutic option; however, despite its use, recurrence with a fatal outcome is common. The lack of molecular characterisation of PMP and other mucinous tumours is mainly due to the physicochemical properties of mucin.

RESULTS

This manuscript describes the first protocol capable of breaking the mucin barrier and isolating proteins from mucinous tumours. Briefly, mucinous tumour samples were homogenised and subjected to liquid chromatography using two specific columns to reduce mainly glycoproteins, albumins and immunoglobulin G. The protein fractions were then subjected to mass spectrometry analysis and the proteomic profile obtained was analysed using various bioinformatic tools. Thus, we present here the first proteome analysed in PMP and identified a distinct mucin isoform profile in soft compared to hard mucin tumour tissues as well as key biological processes/pathways altered in mucinous tumours. Importantly, this protocol also allowed us to identify MUC13 as a potential tumour cell marker in PMP.

CONCLUSIONS

In sum, our results demonstrate that this protein isolation protocol from mucin will have a high impact, allowing the oncology research community to more rapidly advance in the knowledge of PMP and other mucinous neoplasms, as well as develop new and effective therapeutic strategies.

Massive appendiceal mucinous neoplasm diagnosed after abdominal trauma: Pitfalls in imaging and diagnosis

Low grade appendiceal mucinous neoplasm (LAMN) is a rare tumor presenting typically with symptoms of acute appendicitis. A 33-year-old gentleman presented with abdominal fullness and discomfort secondary to abdominal trauma obtained during boxing training. Investigations with magnetic resonance imaging (MRI), ultrasound, and colonoscopy revealed a large cystic lesion in the ascending colon mesentery with unclear continuation with the appendix. There were no obvious features of malignancy. Laparoscopy revealed a large, firm mass connected to the appendix with enlarged lymph nodes, and the patient underwent radical resection with a right hemicolectomy. Histopathology revealed complete excision of LAMN with no lymphatic involvement. Post traumatic intra-abdominal cystic lesions pose a diagnostic challenge, and neoplastic lesions cannot be ruled out with imaging alone, even with benign appearances. Careful surgical excision and histopathological diagnosis is the only definitive method of ruling-out malignancy.

Appendiceal Mucinous Neoplasm: A Case of an Incidental Finding

Appendiceal mucinous neoplasms (AMNs) are uncommon gastrointestinal tumors characterized by mucus accumulation in the appendix. Patients may complain of acute appendicitis-like symptoms with other alarming features, but approximately half of the cases of AMNs are found incidentally on imaging. Early diagnosis and management of these neoplasms are important to prevent malignant progression and complications such as bowel obstruction and pseudomyxoma peritonei. We report a case of a 28-year-old female who initially presented with vomiting and acute left lower abdominal pain radiating to the left flank. Computed tomography (CT) revealed a 1.5 mm stone in the left ureteral vesicular junction and a 2.3 x 2.4 x 5.2 cm cystic tubular mass at the base of the cecum, suspicious of an appendiceal mucocele. An elective laparoscopic appendectomy was performed on this admission, which was converted to a right hemicolectomy due to the pathologic finding of a focally high-grade AMN on intraoperative frozen specimen pathology. This report aims to provide an example of a case of an incidental AMN and how it was diagnosed and managed surgically. AMNs are rare tumors that originate from the appendix and can pose diagnostic and therapeutic challenges due to their diverse clinical presentations and variable histopathological features. The majority of cases of AMNs are discovered in middle-aged individuals (40-50 years of age) after an appendectomy is performed and examined by pathology. This case report aims to describe a rare presentation of a 28-year-old female patient with an incidental finding of AMN on a CT scan of the abdomen while being worked up for suspected nephrolithiasis. We will provide a comprehensive overview of a unique presentation of AMN, highlighting its clinical manifestations, diagnostic approach, and management strategies. We present the case of a 28-year-old female patient who presented to the emergency department with complaints of acute left lower quadrant abdominal pain radiating to the left flank and vomiting. After an initial assessment and workup, which included lab investigations and imaging, a diagnosis of unilateral hydronephrosis due to a calculus of the ureterovesical junction was made. However, there was also suspicion of an appendiceal mucocele, as evidenced by a CT scan of the abdomen and pelvis. On admission day one, under the care and management of the urology team, she passed the stone with complete resolution of the presenting symptoms. On hospital day two, she underwent an elective laparoscopic appendectomy followed by a right hemicolectomy due to findings of high-grade mucinous neoplasm on the resected frozen specimen near the base of the appendix. AMN was an incidental finding based on CT imaging and macroscopic findings, which was later confirmed by histopathological assessment and report.

Progress in Biological Research and Treatment of Pseudomyxoma Peritonei

Pseudomyxoma peritonei (PMP) is a rare disease characterized by extensive peritoneal implantation and mass secretion of mucus after primary mucinous tumors of the appendix or other organ ruptures. Cytoreductive surgery (CRS) combined with hyperthermic intraperitoneal chemotherapy (HIPEC) is currently the preferred treatment, with excellent efficacy and safety, and is associated with breakthrough progress in long-term disease control and prolonged survival. However, the high recurrence rate of PMP is the key challenge in its treatment, which limits the clinical application of multiple rounds of CRS-HIPEC and does not benefit from conventional systemic chemotherapy. Therefore, the development of alternative therapies for patients with refractory or relapsing PMP is critical. The literature related to PMP research progress and treatment was searched in the Web of Science, PubMed, and Google Scholar databases, and a literature review was conducted. The overview of the biological research, treatment status, potential therapeutic strategies, current research limitations, and future directions associated with PMP are presented, focuses on CRS-HIPEC therapy and alternative or combination therapy strategies, and emphasizes the clinical transformation prospects of potential therapeutic strategies such as mucolytic agents and targeted therapy. It provides a theoretical reference for the treatment of PMP and the main directions for future research.

Establishment and characterization of NCC-PMP2-C1: a novel patient-derived cell line of pseudomyxoma peritonei with signet ring cells

Pseudomyxoma peritonei (PMP) is a rare phenomenon, characterized by accumulation of mucus in the abdominal cavity due to a mucinous neoplasm. Histologically, PMP is divided into three prognostic classes, namely low-grade mucinous carcinoma peritonei (LGMCP), high-grade mucinous carcinoma peritonei (HGMCP), and high-grade mucinous carcinoma peritonei with signet ring cells (HGMCP-S); HGMCP-S exhibits the worst prognosis. Complete cytoreductive surgery and hyperthermic intraperitoneal chemotherapy have been established as the standard therapy for PMP. However, 50% of patients with PMP experience a recurrence, and 30-40% are unable to receive the standard treatment due to invasive diseases. Therefore, novel therapies are required for their treatment. Although patient-derived cell lines are important tools for basic and pre-clinical research, PMP cell lines derived from patients with HGMCP-S have never been reported. Thus, we established a novel PMP cell line NCC-PMP2-C1, using surgically resected tumor tissue from a patient with HGMCP-S. NCC-PMP2-C1 cells were maintained for more than five months and passaged 30 times under culture conditions. NCC-PMP2-C1 cells exhibited multiple deletions and somatic mutations, slow growth, histological features, and dissemination of tumor cells in nude mice. Screening for the anti-proliferative effects of anti-cancer drugs on cells revealed that bortezomib, mubritinib, and romidepsin had a significant response against NCC-PMP2-C1 cells. Thus, the NCC-PMP2-C1 cell line is the first PMP cell line harboring signet ring cells and will be a valuable resource for basic and preclinical studies of HGMCP-S.

Active surveillance for low-grade appendiceal mucinous neoplasm (LAMN)

Objectives

Due to the scarcity of low-grade appendiceal mucinous neoplasm (LAMN), there is an absence of systematized guidelines concerning its management, especially after incidental finding on an appendiceal specimen. In this study, we evaluate the active surveillance (AS) strategy adopted for a series of patients diagnosed with LAMN on resection specimens who were considered to have a low risk of pseudomyxoma progression.

Methods

Thirty patients were included between April 2014 and July 2021, with a female majority and a median follow-up period of 3.1 years. The inclusion criteria were as follows: LAMN diagnosis on appendiceal specimens, confirmed in an expert center, limited extra-appendiceal mucin resected and localized around the appendix, normal biology (CEA, CA199, CA125) and normal abdominopelvic MRI. AS included physical exam (trocar scar), biology and MRI, 6 months postoperatively, then yearly for 10 years.

Results

As an initial surgery, 77 % had an appendectomy as their initial intervention, 17 % had a cecectomy, and 6 % had a right colectomy. After follow-up, 87 % of patients showed no sign of disease progression by MRI, while 13 % progressed to PMP. MRI performed in the first postoperative year predicted the disease prognosis in 97 % of patients.

Conclusions

The AS strategy, based on MRI, is a valid option after incidental LAMN diagnosis.

Clinical Effectiveness of Preoperative 18F-FDG PET/CT in Predicting Pathological Tumor Grade in Patients with Pseudomyxoma Peritonei Originating from Appendix: A Retrospective Cohort Study

BACKGROUND

Cytoreductive surgery combined with hyperthermic intraperitoneal chemotherapy is the standard treatment for patients with pseudomyxoma peritonei (PMP). In some malignancies, the standard uptake value of positron emission tomography with 2-deoxy-2-18F-fluoro-D-glucose integrated with computed tomography (18F-FDG PET/CT) is now accepted as a reliable indicator of neoplastic behavior. This study aimed to evaluate the association between the maximum standardized uptake value (SUVmax) and pathological grade in patients with PMP and to investigate the significance of SUVmax in the preoperative assessment of these patients.

PATIENTS AND METHODS

In this retrospective single-center study, consecutively enrolled patients diagnosed with PMP of appendiceal origin underwent preoperative 18F-FDG PET/CT. SUVmax was calculated as the highest SUVmax value in the abdomen excluding the primary site. SUVmax was compared with the pathological grade (low or high grade) of PMP tumors according to the World Health Organization classification and further analyzed with respect to the estimated cutoff point, sensitivity, specificity, and receiver operating characteristic.

RESULTS

In total, 160 patients were included. CRS was successfully performed in 93 patients and palliative debulking surgery in 67 patients. The pathological grade was high in 45 patients and low in 115. High-grade patients had a higher median SUVmax on 18F-FDG PET/CT than did low-grade patients (3.83 versus 2.34, p < 0.001). The highest area under the curve was 0.81, with a sensitivity of 77.8%, specificity of 72.3%, and cutoff point of 2.63.

CONCLUSION

This study suggests that the SUVmax of preoperative 18F-FDG PET/CT is associated with the pathological grade in patients with PMP.

Peritoneal dissemination of appendiceal goblet cell adenocarcinoma mimicking white pus caused by peritonitis following appendicitis: an instructive case report

BACKGROUND

Goblet cell adenocarcinoma is an extremely rare tumor in which the same cells exhibit both mucinous and neuroendocrine differentiation. It is considered more aggressive compared to conventional carcinoids and more likely to cause metastasis.

CASE PRESENTATION

We report a case of goblet cell adenocarcinoma with peritoneal metastases. A 62-year-old man underwent appendectomy for acute appendicitis. Intraoperatively, inflammatory white pus and a small amount of dirty ascites were observed in the lower abdomen with severely inflamed appendix. Histopathological examination of the specimen collected during appendectomy revealed goblet cell adenocarcinoma with a positive surgical margin. One month later, additional ileal resection was planned. Laparoscopic examination revealed disseminated nodules throughout the abdominal cavity. Therefore, the patient underwent resection of the peritoneal nodules. The peritoneal specimens confirmed the histopathological findings. Thus we diagnosed the patient with peritoneal dissemination of appendiceal goblet cell adenocarcinoma.

CONCLUSIONS

In cases wherein white pus is observed during surgery for acute appendicitis, considering the possibility of dissemination, collecting samples for histopathological examination, and initiating early treatment are crucial.

Global trends in research of pseudomyxoma peritonei: a bibliometric and visualization analysis

Objective

Pseudomyxoma peritonei (PMP) was a complex disease that had attracted increasing attention. However, there had been no bibliometric analysis of this disease so far. This study aimed to explore the current situation and frontier trend of PMP through bibliometric and visualization analysis, and to indicate new directions for future research.

Methods

The original research articles and reviews related to the PMP research were downloaded from Web of Science Core Collection on September 11, 2023. CiteSpace (6.2.R4) and VOSviewer(1.6.18) were used to perform bibliometric analysis of the publications, and establish the knowledge map. The data collected was analyzed using the Online Analysis Platform of Bibliometric to evaluate the cooperation of countries in this field.

Results

We identified 1449 original articles and reviews on PMP published between 1998 and 2023. The number of publications on PMP increased continuously. The United States, the United Kingdom and China were the top contributors. The most productive organization was the MedStar Washington Hospital Center. Sugarbaker, Paul H. was the most prolific author and the most cited. Keyword analysis showed that "Pseudomyxoma peritonei", "cancer", "cytoreductive surgery", and "hyperthermic intraperitoneal chemotherapy" were the most common keywords. The earliest and latest used keywords were "mucinous tumors" and "impact", respectively. "classification", "cytoreductive surgery", "appendiceal" were the top 3 strongest citation bursts. The reference "Carr NJ, 2016, AM J SURG PATHOL" had the highest co-citations.

Conclusion

This bibliometric analysis showed an increasing trend in literature related to PMP. The research trends and hotspots identified in this study could guide the future research directions in this field, in order to promote the development of PMP.

A case of pseudomyxoma peritonei arising from a perforated intraductal papillary mucinous neoplasm that underwent cytoreductive surgery and hyperthermic intraperitoneal chemotherapy

Pseudomyxoma peritonei (PMP) of pancreatic origin arising from an intraductal papillary mucinous neoplasm (IPMN) is rare. Cytoreductive surgery (CRS) with hyperthermic intraperitoneal chemotherapy (HIPEC) has been established as the optimal treatment for PMP. However, the benefits and safety of CRS with HIPEC for treating PMP of pancreatic origin remain unclear. Herein, we describe a case of PMP of pancreatic origin that was treated with CRS and HIPEC without postoperative complications. A 75-year-old woman was referred to our department. Computed tomography (CT) revealed a multilocular cystic tumor in the pancreatic tail, notable mucinous ascites in the abdominal cavity, and scalloping of the liver and spleen. CT did not reveal the appendix, and the ovaries were normal in size. The patient was diagnosed with PMP of pancreatic origin, and CRS and HIPEC were performed. Intraoperatively, the pancreatic tumor was perforated, and there was a large amount of mucinous ascites. We performed distal pancreatectomy in addition to CRS and HIPEC, with no intraoperative complications. The postoperative course was uneventful, and the patient survived after 6 months without recurrence. CRS with HIPEC may be a feasible treatment option for PMP of pancreatic origin.

Appendiceal mucinous neoplasm in adolescence: Diagnosis, management, and surveillance

This case report describes a 17-year-old patient with a low-grade appendiceal mucinous neoplasm. The patient presented with non-bloody diarrhea, abdominal pain, and weight loss. A colonoscopy revealed a cecal polypoid mass that required laparoscopic surgery. The residual appendix was dilated with myxoglobulosis and histopathology confirmed the diagnosis of a low-grade appendiceal mucinous neoplasm staged pT3Nx. The potential risk of pseudomyxoma peritonei is a serious complication of these tumors. Surveillance plans include computed tomography abdomen and pelvis, and tumor markers every 6 months for the next 2 years. This case highlights the importance of considering appendiceal malignancy in patients with abdominal pain and weight loss, despite the rarity of the disease. It also emphasizes the need for careful monitoring due to the possible complications associated with these tumors. Treatment and prognosis for appendiceal neoplasms depend on the histopathologic characteristics, tumor-nodes-metastasis stage, tumor grade, and presence of peritoneal disease.

Genome-Wide Analysis of DNA Methylation in Pseudomyxoma Peritonei Originated from Appendiceal Neoplasms

INTRODUCTION

Pseudomyxoma peritonei (PMP) is a disease characterized by progressive accumulation of intraperitoneal mucinous ascites produced by neoplasms in the abdominal cavity. Since the prognosis of patients with PMP remains unsatisfactory, the development of effective therapeutic drug(s) is a matter of pressing concern. Genetic analyses of PMP have clarified the frequent activation of GNAS and/or KRAS. However, the involvement of global epigenetic alterations in PMPs has not been reported.

METHODS

To clarify the genetic background of the 15 PMP tumors, we performed genetic analysis using AmpliSeq Cancer HotSpot Panel v2. We further investigated global DNA methylation in the 15 tumors and eight noncancerous colonic epithelial tissues using MethylationEPIC array BeadChip (Infinium 850k) containing a total of 865,918 probes.

RESULTS

This is the first report of comprehensive DNA methylation profiles of PMPs in the world. We clarified that the 15 PMPs could be classified into at least two epigenotypes, unique methylation epigenotype (UME) and normal-like methylation epigenotype (NLME), and that genes associated with neuronal development and synaptic signaling may be involved in the development of PMPs. In addition, we identified a set of hypermethylation marker genes such as HOXD1 and TSPYL5 in the 15 PMPs.

CONCLUSIONS

These findings may help the understanding of the molecular mechanism(s) of PMP and contribute to the development of therapeutic strategies for this life-threatening disease.

Appendiceal Mucinous Neoplasms and Inflammatory Bowel Disease: Systematic Review of the Literature

There is no clear evidence on the prevalence and clinical presentation of appendiceal mucinous neoplasm (AMN) among patients with inflammatory bowel disease (IBD), so a systematic review was performed to investigate the diagnosis, management and treatment of AMN in these patients. PubMed, Medline, Scopus and the Cochrane Library were searched for articles published up to September 2023. Twenty-three studies reporting data about 34 AMN patients were included. UC patients had a median age of 52 years and a median length of disease of 10 years; CD patients had a median age of 40.5 years and a median length of disease of 5 years. A pre-operative diagnosis was achieved in 44% of patients. Most patients were symptomatic (82.6%) and showed moderate-severe disease activity (61%). Surgical procedures were performed: laparoscopic appendectomy, ileocecal resection, right hemicolectomy and colectomy/proctocolectomy. Of the patients, 73.5% were diagnosed with low-grade mucinous neoplasm (LAMN) and nine with adenocarcinoma. Synchronous colorectal dysplasia/carcinoma was present in 23.5% of patients. IBD patients with long-standing disease should be routinely screened, not only for colorectal cancer but also for AMN, during gastro-enterologic follow-up. Laparoscopic appendectomy of unruptured LAMN as well as right hemicolectomy of non-metastatic adenocarcinoma are safe procedures in IBD patients.

Mytomicin-C, Metronomic Capecitabine, and Bevacizumab in Patients With Unresectable or Relapsed Pseudomyxoma Peritonei of Appendiceal Origin

INTRODUCTION

Pseudomyxoma peritonei (PMP) is a rare, slow growing tumor, traditionally considered chemoresistant. The only curative approach is cytoreductive surgery (CRS) followed by hyperthermic intraperitoneal chemotherapy (HIPEC). At disease relapse, or in patients with inoperable disease at diagnosis, no standard treatment has been defined, though nonrandomized series showed promising results with fluoropyrimidine-based regimens.

PATIENTS AND METHODS

We conducted a prospective study in patients with relapsed or unresectable PMP and confirmed disease progression at baseline. Patients received MMC (7 mg/m2 every 6 weeks, up to a maximum of 4 cycles) plus metronomic capecitabine (625 mg/sqm/day b.i.d.) and bevacizumab (7.5 mg/kg every 3 weeks) until disease progression, unacceptable toxicity, or consent withdrawal. Primary endpoint was progression-free survival (PFS); secondary endpoints were overall survival (OS), overall response rate according to RECIST v1.1 criteria, serum markers response and safety.

RESULTS

Fifteen patients were included. At a median follow-up of 26.1 months (IQR, 17.7-49.6), median PFS was 17.9 months (95% CI, 11.0-NE), with 1-year PFS and OS rates of 73% and 87%. Safety profile was manageable, with only 13% G3/G4 treatment-related adverse events.

CONCLUSION

Metronomic capecitabine, bevacizumab, and MMC are an active regimen in advanced and progressive PMP and favorably compares with historical series.

Low-grade appendiceal mucinous neoplasm encountered during risk-reducing salpingo-oophorectomy: A case of laparoscopic surgery

Low-grade appendiceal mucinous neoplasm (LAMN) is a rare epithelial malignancy of the appendix. If it perforates the abdominal cavity, it can cause a serious clinical syndrome called pseudomyxoma peritonei. In the present case, we laparoscopically removed a LAMN encountered during risk-reducing salpingo-oophorectomy (RRSO). The patient was a 53-year-old woman who was diagnosed with hereditary breast and ovarian cancer syndrome. RRSO was planned, and magnetic resonance imaging revealed a large cystic tumor in the right lower abdomen. We expected an ovarian cyst; however, it was a primary tumor of the appendix. Partial cecal resection was performed laparoscopically by a surgical oncologist. The pathological diagnosis was LAMN. Gynecologists may encounter this disease incidentally. Mucinous appendiceal neoplasm (MAN) may be encountered during RRSO. If a right lower abdominal mass is found near a normal ovary preoperatively, gynecologists should consider MAN as well as paraovarian cyst.

Appropriate Imaging for Geriatric Trauma

BACKGROUND

Trauma is the leading cause of preventable death in the United States. Early detection of life-threatening injuries leads to improved survival. Computed tomography (CT) scanning has become the modality of choice for early detection of injuries in the stable patient. Some studies have associated selective imaging (Selective-CT) with equivalent outcomes compared to whole body imaging (Pan-CT) with lower costs and radiation exposure. Within the geriatric population, however, the utility of Pan-CT remains controversial. Therefore, the aim of this study was to determine if a difference exists between Selective-CT and Pan-CT imaging in the geriatric trauma patient.

METHODS

A retrospective analysis of Level 3 (G60) trauma activations presenting to our urban Level I trauma center between June 2016 and June 2019 was performed. Pan-CT was defined by ICD-10 codes indicating a head, cervical spine, chest, abdomen, and pelvis CT series. Patients with missing images and those who were transferred from other institutions were excluded. Logistic regression controlling for age, gender, injury type, severity, and Glasgow Coma Score was performed.

RESULTS

A total of 1014 patients met inclusion criteria. Of these, 30.9% underwent Pan-CT (n = 314), 48.9% had Selective-CT (n = 497), and 20.2% received no CT imaging (n = 203). After logistic regression, no clinically significant variations in emergency department length of stay (LOS), hospital LOS, ICU LOS, ventilator days, discharge disposition, missed injury rate, or mortality rate were observed between imaging strategies.

CONCLUSIONS

Pan-CT provides no clinically significant advantage over Selective-CT in the geriatric trauma patient.

Long-term survival in patients with PMP: a single-institutional retrospective study from China

BACKGROUND

As the standard treatment for pseudomyxoma peritonei (PMP), cytoreductive surgery (CRS) plus hyperthermic intraperitoneal chemotherapy (HIPEC) can significantly prolong the survival of PMP patients, and some patients can even achieve long-term survival (LTS) or clinical cure. The purpose of this study was to analyze the clinicopathological and treatment features of PMP patients with LTS and to explore the survival benefit factors of PMP patients.

METHODS

The clinicopathological and prognostic data of PMP patients who received CRS + HIPEC at our center from December 2004 to May 2023 were retrospectively analyzed. PMP patients were divided into LTS group (≥ 10 years) and short-term survival (STS) group (< 5 years) according to the length of natural history. Univariate and multivariate analyses were performed to explore the beneficial factors of PMP patients with LTS.

RESULTS

A total of 609 patients with PMP received CRS + HIPEC treatment at our center. Two-hundred one patients with PMP were included in the study after screening, including 39 patients (19.4%) in the LTS group and 162 patients (80.6%) in the STS group. In STS group and LTS group, median overall survival based on natural history was 29.2 (2.4-59.9) vs. 138.9 (120.3-416.7) months. Univariate analysis revealed 8 factors (P < 0.05) with statistically significant differences between the two groups: gender, chemotherapy history, previous surgical score, Karnofsky Performance Status score, pathological diagnosis, lymphatic metastasis, peritoneal cancer index, and completeness of cytoreduction (CC). Multivariate analysis identified only two factors independently associated with LTS of PMP patients: CC and pathological diagnosis.

CONCLUSION

Complete CRS and pathological features are two key factors affecting LTS in PMP patients.

Defining a role for systemic chemotherapy in local and advanced appendix adenocarcinoma

BACKGROUND

Appendix adenocarcinomas (AAs) are rare tumours that often present late, with a propensity for peritoneal metastases (PMs). This study aimed to evaluate outcomes of AA patients undergoing cytoreductive surgery (CRS) with curative intent and determine the role of systemic chemotherapy.

MATERIALS AND METHODS

Data were collected from a prospective database and classified according to World Health Organization (WHO) 2019 classification. Tumour clearance from CRS was described using a completeness of cytoreduction (CC) score ranging from 0 [no residual disease (RD)] to 3 (>2.5 cm RD). Patients with CC0-2 CRS received hyperthermic intraperitoneal chemotherapy (HIPEC). Systemic chemotherapy was categorised as 'prior' (>6 months before), 'neoadjuvant' (<6 months before), 'adjuvant' (<6 months after CC0-1 CRS) or 'palliative' (after CC2-3 CRS). Analyses used Kaplan-Meier and Cox regression methods.

RESULTS

Between January 2005 and August 2021, 216 AA patients were identified for inclusion. Median age was 59 years (21-81 years). CRS/HIPEC was carried out in 182 (84%) patients, of whom 164/182 (76%) had mitomycin C HIPEC. CC0-1 was achieved in 172 (80%) patients. Systemic chemotherapy was given to 97 (45%) patients from the whole cohort and to 37/46 (80%) patients with positive nodes. Median overall survival (OS) was 122 months (95% confidence interval 61-182 months). After multivariate analysis, patients with acellular and lower-grade PM had similar OS to those with localised (M0) disease (P = 0.59 and P = 0.19). For patients with positive nodes, systemic chemotherapy was associated with reduced risk of death compared to no chemotherapy (P < 0.0019).

CONCLUSION

This study identifies AA patients with positive lymph nodes derive the most benefit from systemic chemotherapy. We confirm the prognostic importance of stage and peritoneal grade, with excellent outcomes in patients with acellular mucin and lower-grade PM.

[Incidental finding of appendiceal mucinous neoplasms]

Low-grade appendiceal mucinous neoplasms (LAMN) are rare and are diagnosed in at least 0.13% of appendectomies in Germany, although significant underreporting is likely. Perforation of the tumors can result in abdominal mucinous collections, so-called pseudomyxoma peritonei (PMP). The challenge in the treatment of LAMN is the adequate approach to the incidental finding of these tumors. If a mucinous neoplasm is preoperatively suspected in cases of an acute condition, usually appendicitis, it must be weighed up whether a conservative approach is justifiable or whether immediate appendectomy is necessary. If this is the case, an intraoperative perforation of the appendix must be avoided and the complete abdominal cavity must be inspected for mucin deposits. If conservative treatment is possible, further treatment should take place at a specialized center. If the neoplasm is first found incidentally during surgery, perforation of the appendix should also be avoided and the entire abdominal cavity should be inspected for a PMP. If a PMP is present cytoreduction and hyperthermic intraperitoneal chemotherapy (HIPEC) should be performed in a specialized center. If LAMN are found during the postoperative histological work-up, it should be evaluated whether a perforation was present and mucin collections are noted in the surgical report. In the case of LAMN without evidence of a PMP, appendectomy is the adequate treatment. In cases of intra-abdominal mucinous collections, samples should be taken and further treatment should be performed at a center with sufficient expertise. An ileocecal resection or oncological hemicolectomy is not indicated. After adequate treatment, all patients should receive a follow-up using cross-sectional imaging (preferably magnetic resonance imaging, MRI) and determination of the tumor markers CEA, CA 19-9 and CA 125.

[Surgical treatment of pseudomyxoma peritonei-Cytoreductive surgery and hyperthermic intraperitoneal chemotherapy]

BACKGROUND

Pseudomyxoma peritonei syndrome (PMP) is an orphan disease. Surgery is the fundament of treatment.

METHOD

Short review summarizing the state of the art treatment.

RESULTS

Cytoreductive surgery (CRS) in combination with hyperthermic intraperitoneal chemotherapy (HIPEC) form the foundations of treatment for PMP. The peritoneal cancer index should be preoperatively determined based on imaging and/or laparoscopy, intraoperatively validated and both should be documented. An extraperitoneal surgical preparation technique leads to effective en bloc resection of the peritoneum and the affected abdominal area. The HIPEC technique should be performed with mitomycin C for 60-90 min. Complete CRS (CC = 0, CC = 1) and the histological subtype are relevant for the prognosis. Structured educational programs and mentoring can optimize the learning curve. The aftercare should be performed at the surgical center. After follow-up imaging at 3 months after CRS, in the first 2 years a control should be carried out every 6 months. Thereafter, the intervals can be extended to 1 year.

CONCLUSION

Standardized surgical treatment and HIPEC, optimized specific surgical training and structured follow-up at the center lead to an excellent long-term prognosis for patients with PMP.