Patients with pseudomyxoma peritonei associated with disseminated peritoneal adenomucinosis have a significantly more favorable prognosis than patients with peritoneal mucinous carcinomatosis

The Vermiform Appendix and Its Pathologies

The vermiform appendix is a muscular cylindrical structure originating near the junction of the cecum and ileum, averaging 9 cm (5-35 cm) in size. As the most mobile viscera, it can adopt several positions, the most common being the retrocecal position. Perceived as an atavistic organ lacking physiological relevance, the vermiform appendix appears to be involved in immune function, serving in the maturation of B lymphocytes and the production of immunoglobulin A, in endocrine function, excreting amines and hormones in the 2-3 mL of mucus secreted daily, and in digestive function, by storing beneficial bacteria from where they can recolonize the colon. With a lumen of about 6 mm, the vermiform appendix has a reduced storage capacity, so any blockage of the appendix with fecoliths (fecaliths), seeds derailed from the colon, or enlarged lymph nodes prevents drainage and intraluminal accumulation of secreted mucus. Unable to relax, the appendix wall severely limits its intraluminal volume, so mucus accumulation leads to inflammation of the appendix, known generically as appendicitis. In addition, the vermiform appendix may be the site of the development of neoplastic processes, which may or may not involve mucus production, some of which can significantly affect the standard of living and ultimately lead to death. In general, mucinous tumors may have a better prognosis than non-mucinous tumors. This review takes a comprehensive path, starting by describing the anatomy and embryology of the vermiform appendix and further detailing its inflammatory pathologies, pathologies related to congenital anomalies, and appendix tumors, thus creating an up-to-date framework for better understanding, diagnosis, and treatment of these health problems.

Unravelling Peritoneal Carcinomatosis Using Cross-Sectional Imaging Modalities

Peritoneal carcinomatosis (PC) refers to malignant epithelial cells that spread to the peritoneum, principally from abdominal malignancies. Until recently, PC prognosis has been considered ill-fated, with palliative therapies serving as the only treatment option. New locoregional treatments are changing the outcome of PC, and imaging modalities have a critical role in early diagnosis and disease staging, determining treatment decision making strategies. The aim of this review is to provide a practical approach for detecting and characterizing peritoneal deposits in cross-sectional imaging modalities, taking into account their appearances, including the secondary complications, the anatomical characteristics of the peritoneal cavity, together with the differential diagnosis with other benign and malignant peritoneal conditions. Among the cross-sectional imaging modalities, computed tomography (CT) is widely available and fast; however, magnetic resonance (MR) performs better in terms of sensitivity (92% vs. 68%), due to its higher contrast resolution. The appearance of peritoneal deposits on CT and MR mainly depends on the primary tumour histology; in case of unknown primary tumour (3-5% of cases), their behaviour at imaging may provide insights into the tumour origin. The timepoint of tumour evolution, previous or ongoing treatments, and the peritoneal spaces in which they occur also play an important role in determining the appearance of peritoneal deposits. Thus, knowledge of peritoneal anatomy and fluid circulation is essential in the detection and characterisation of peritoneal deposits. Several benign and malignant conditions show similar imaging features that overlap those of PC, making differential diagnosis challenging. Knowledge of peritoneal anatomy and primary tumour histology is crucial, but one must also consider clinical history, laboratory findings, and previous imaging examinations to achieve a correct diagnosis. In conclusion, to correctly diagnose PC in cross-sectional imaging modalities, knowledge of peritoneal anatomy and peritoneal fluid flow characteristics are mandatory. Peritoneal deposit features reflect the primary tumour characteristics, and this specificity may be helpful in its identification when it is unknown. Moreover, several benign and malignant peritoneal conditions may mimic PC, which need to be considered even in oncologic patients.

Appendiceal Mucinous Neoplasms: From Clinic to Pathology and Prognosis

Appendiceal mucinous neoplasms have been classified differently over time causing confusion when comparing results between working groups in this field and establishing a prognosis of the disease. A historical perspective of the different classification systems of these tumors is essential for the understanding of the evolution of concepts and histopathological definitions that have led up to the present moment. We carried out a systematic review of the pathological classifications of appendiceal mucinous tumors and how they have included the new criteria resulting from clinical and pathological research. The latest classifications by PSOGI and AJCC 8th edition Cancer Staging have made a great effort to incorporate the new pathological descriptions and develop prognostic groups. The introduction of these new classification systems has posed the challenge of verifying how they adapt to our casuistry and which one defines best the prognosis of our patients. We reclassified our series of patients treated for mucinous appendiceal tumors with cytoreductive surgery and hyperthermic intraperitoneal chemotherapy following the PSOGI and the AJCC 8th edition criteria and concluded that both classifications correspond well with the OS and DFS of these patients, with some advantage relative to the PSOGI classification due to a better histopathological description of the different groups.

Which classification system defines best prognosis of mucinous neoplasms of the appendix with peritoneal dissemination: TNM vs PSOGI?

AIMS

Several classification systems are used for pseudomyxoma peritonei. The four-tiered classification system proposed by Peritoneal Surface Oncology Group International (PSOGI) and the two-tiered proposed by the eighth edition of the American Joint Committee on Cancer (AJCC) result from evolution in terminology and pathological insight. The aim is to evaluate the impact of PSOGI and eighth edition of the AJCC classifications on survival.

METHODS

Pathological slides were reviewed from a prospectively maintained database including patients treated with cytoreductive surgery and hyperthermic intraperitoneal chemotherapy for an appendiceal mucinous neoplasm with peritoneal dissemination between January 2009 and December 2019. Patients were reclassified according to PSOGI and AJCC eighth edition criteria. Survival analysis evaluated the impact of each classification system on overall survival (OS) and disease-free survival (DFS) while the concordance-index evaluated their predictive power.

RESULTS

95 patients were identified; 21.1% were reclassified as acellular mucin, 55.8% as low-grade mucinous carcinoma peritonei, 8.4% as high-grade MCP (HGMCP) and 14 as HGMCP with signet ring cells. Median OS was not reached, 5-year OS and DFS were 86.1% and 51.5%, respectively. Multivariate analysis revealed significant associations with OS (PSOGI: HR 10.2, p=0.039; AJCC: HR 7.7, p=0.002) and DFS (PSOGI: HR 12.7, p=0.001; AJCC: HR 3.7, p<0.001). The predictive capacity of both classification systems was unacceptable for OS and DFS (concordance-index values <0.7).

CONCLUSIONS

Both classification systems behaved similarly when stratifying our series into prognostic groups. The PSOGI classification provides better histopathological description, but histology alone is insufficient for adequate patient prognostication.

Prognostic significance of acellular mucin in patients undergoing cytoreductive surgery and hyperthermic intraperitoneal chemotherapy (CRS/HIPEC) for appendiceal neoplasms

INTRODUCTION

Appendiceal neoplasms have a propensity for peritoneal dissemination. The standard of care for select individuals is CRS/HIPEC. In the current 8^th AJCC Staging system, a finding of only intraperitoneal acellular mucin (M1a) is classified as Stage IVa. There is concern that the current AJCC system may over-stage patients.

METHODS

This was a single-institution retrospective review of 164 cases of mucinous appendiceal neoplasm. Patients undergoing CRS/HIPEC with M1a disease were compared to patients with peritoneal deposits containing tumor cells (well-differentiated adenocarcinoma; low-grade mucinous carcinoma peritonei-M1b,G1). Overall and recurrence-free survival were assessed.

RESULTS

Median age was 51 years, 70% were female, and 75% White. Sixty-four patients had M1a disease and 100 M1b,G1 disease. M1a disease had a lower median PCI score (11 vs. 20, p = .0001) and a higher rate of complete CRS (62% vs. 50%, p = .021). Median follow-up was 7.6 years (IQR 5.6-10.5 years). For M1a disease, there were no recurrences and only one patient died during the study interval. In comparison, for M1b disease, 66/100 (66%) recurred with a 5-year RFS of 40.5% (HR 8.0, 95% CI 4.9-15.1, p < .0001), and 31/100 (31%) died with a 5-year OS of 84.8% (HR 4.5, 95% CI 2.2-9.2, p < .0001).

CONCLUSIONS

Acellular mucin (M1a disease) after CRS/HIPEC for appendiceal neoplasm is associated with longer OS and RFS compared to M1b, G1 disease. Current AJCC staging does not accurately reflect the differing outcomes of these two patient populations. The presence of acellular mucin in the peritoneal cavity should not be perceived as a metastatic equivalent.

The role of chemotherapy in the treatment of advanced appendiceal cancers: summary of the literature and future directions

Appendiceal cancer is rare and encompasses a diverse group of tumours ranging from low-grade appendiceal mucinous neoplasms to high-grade adenocarcinomas. Appendiceal cancers often spread to the peritoneal cavity causing extensive mucinous dissemination and peritoneal metastases. Prognosis varies with histological subtype. Cytoreductive surgery and heated intraperitoneal chemotherapy is well-established as the most effective treatment achieving long-term survival in some patients. Chemotherapy regimens used to treat appendiceal cancer are extrapolated from the colorectal cancer setting, but disease biology differs and outcomes are inferior. The role of chemotherapy in the treatment of appendiceal cancer remains poorly defined. There is an urgent need to develop novel tailored treatment strategies in the perioperative and unresectable setting. This review aims to evaluate the literature for patients who received intraperitoneal and systemic chemotherapy for appendiceal cancers.

Identification of a novel mechanism for reversal of doxorubicin-induced chemotherapy resistance by TXNIP in triple-negative breast cancer via promoting reactive oxygen-mediated DNA damage

Given that triple-negative breast cancer (TNBC) lacks specific receptors (estrogen and progesterone receptors and human epidermal growth factor receptor 2) and cannot be treated with endocrine therapy, chemotherapy has remained the mainstay of treatment. Drug resistance is reportedly the main obstacle to the clinical use of doxorubicin (DOX) in this patient population. Accordingly, screening molecules related to chemoresistance and studying their specific mechanisms has clinical significance for improving the efficacy of chemotherapy in TNBC patients. Thioredoxin-interacting protein (TXNIP) is a metabolism-related protein that plays a tumor suppressor role in various malignant tumors; however, the specific role of TXNIP in tumor chemoresistance has not been reported. In the present study, we explored the potential molecular mechanism of TXNIP in the chemoresistance of TNBC for the first time. The results showed that TXNIP inhibited the proliferation of TNBC drug-resistant cells and promoted apoptosis in vitro and in vivo. Furthermore, TXNIP promoted the synthesis of reactive oxygen species (ROS) and the accumulation of DNA damage caused by DOX and increased γ-H2AX levels in a time and dose-dependent manner. Moreover, ROS scavenger pretreatment could block DNA damage induced by TXNIP and restore the resistance of TNBC resistant cells to DOX to a certain extent. In addition, we found that the small molecule c-Myc inhibitor 10058-F4 promoted TXNIP expression, increased ROS synthesis in cells, and could enhance the cytotoxicity of chemotherapy drugs in vitro and in vivo when combined with DOX. These results indicated that c-Myc inhibitor 10058-F4 could induce TXNIP upregulation in TNBC drug-resistant cells, and the upregulated TXNIP increased the accumulation of ROS-dependent DNA damage, thereby decreasing chemotherapy resistance of TNBC. Our findings reveal a new mechanism of mediating drug resistance and provide a new drug combination strategy to overcome DOX resistance in TNBC.

Radiomics analysis based on CT's greater omental caking for predicting pathological grading of pseudomyxoma peritonei

The objective of this study was to predict the preoperative pathological grading and survival period of Pseudomyxoma peritonei (PMP) by establishing models, including a radiomics model with greater omental caking as the imaging observation index, a clinical model including clinical indexes, and a combined model of these two. A total of 88 PMP patients were selected. Clinical data of patients, including age, sex, preoperative serum tumor markers [CEA, CA125, and CA199], survival time, and preoperative computed tomography (CT) images were analyzed. Three models (clinical model, radiomics model and combined model) were used to predict PMP pathological grading. The models’ diagnostic efficiency was compared and analyzed by building the receiver operating characteristic (ROC) curve. Simultaneously, the impact of PMP’s different pathological grades was evaluated. The results showed that the radiomics model based on the CT’s greater omental caking, an area under the ROC curve ([AUC] = 0.878), and the combined model (AUC = 0.899) had diagnostic power for determining PMP pathological grading. The imaging radiomics model based on CT greater omental caking can be used to predict PMP pathological grading, which is important in the treatment selection method and prognosis assessment.

Progression of perforated cystadenoma of the appendix to pseudomyxoma peritonei over 18 years. A case report

INTRODUCTION AND IMPORTANCE

In the past, mucinous appendiceal neoplasms (MAN) greater than 2 cm in diameter were treated by a right colon resection. New data shows that treatment options are to be determined by the histopathologic grade of the appendiceal tumor and the condition of the wall of the appendix (intact vs. breached).

CASE PRESENTATION

A 39-year-old woman had an incidental diagnosis of a low-grade appendiceal mucinous neoplasm (LAMN) at the time of a hysterectomy. The appendiceal tumor had small quantities of mucus surrounding an enlarged appendix. No tumor cells were seen in the mucus by histologic study. The patient was placed in follow-up. Eighteen years later she required treatment for advanced pseudomyxoma peritonei.

CLINICAL DISCUSSION

When 5 different histopathologic types of MAN are considered with an intact vs. perforated wall of the appendix, four different treatment options develop. With LAMN and well or moderately differentiated mucinous appendiceal adenocarcinoma (MACA), the patient does not require operative intervention if the wall of the appendix is intact. If mucus or mucus plus tumor cells are identified outside the appendix an intervention is indicated. In patients, as the one presented, in whom only small amounts of mucus are outside the appendix, surveillance may be recommended.

CONCLUSIONS

In patients with a diagnosed low-grade MAN, dissemination to regional lymph nodes is rare. Dissemination to the peritoneal space places the patient at risk to develop pseudomyxoma peritonei. As this case report illustrates, if surveillance is recommended, long-term follow-up is required.

Defining stage in mucinous tumours of the appendix with peritoneal dissemination: the importance of grading terminology: systematic review

Background

Mucinous appendiceal neoplasms with peritoneal dissemination (PD) show a wide spectrum of clinical behaviour. Histological grade has been correlated with prognosis, but no universally accepted histological grading has been established. The aim of this systematic review was to provide historical insight to understand current grading classifications, basic histopathological features of each category, and to define which classification correlates best with prognosis.

Methods

MEDLINE and the Cochrane Library were searched for studies that reported survival across different pathological grades in patients with mucinous neoplasm of the appendix with PD treated with cytoreductive surgery and hyperthermic intraperitoneal chemotherapy. PRISMA guidelines were followed.

Results

Thirty-eight studies were included. Ronnett’s classification was the most common (9 studies). Classifications proposed by the Peritoneal Surface Oncology Group International (PSOGI) (6 studies) and the seventh or eighth edition of the AJCC (7 studies) are gaining in popularity. Nine studies supported a two-tier, 12 a three-tier, and two a four-tier classification system. Three studies demonstrated that acellular mucin had a better prognosis than low-grade pseudomyxoma peritonei in the PSOGI classification or M1bG1 in the eighth edition of the AJCC classification. Four studies demonstrated that the presence of signet ring cells was associated with a worse outcome than high-grade pseudomyxoma peritonei in the PSOGI classification and M1bG2 in the eighth edition of the AJCC.

Conclusion

There is a great need for a common language in describing mucinous neoplasms of the appendix with PD. Evolution in terminology as a result of pathological insight turns the four-tiered PSOGI classification system into a coherent classification option.

Standardization of the pathologic diagnosis of appendiceal mucinous neoplasms

Although the understanding of appendiceal mucinous neoplasms (AMNs) and their relationship with disseminated peritoneal mucinous disease have advanced, the diagnosis, classification, and treatment of AMNs are still confusing for pathologists and clinicians. The Gastrointestinal Pathology Study Group of the Korean Society of Pathologists (GPSG-KSP) proposed a multicenter study and held a workshop for the “Standardization of the Pathologic Diagnosis of the Appendiceal Mucinous Neoplasm” to overcome the controversy and potential conflicts. The present article is focused on the diagnostic criteria, terminologies, tumor grading, pathologic staging, biologic behavior, treatment, and prognosis of AMNs and disseminated peritoneal mucinous disease. In addition, GPSG-KSP proposes a checklist of standard data elements of appendiceal epithelial neoplasms to standardize pathologic diagnosis. We hope the present article will provide pathologists with updated knowledge on how to handle and diagnose AMNs and disseminated peritoneal mucinous disease.

Hyperthermic Intraperitoneal Chemotherapy (HIPEC) in the management of peritoneal surface malignancies - An evidence-based review

BACKGROUND

Traditionally, peritoneal surface malignancies (PSM) were considered terminal diseases because of their advanced nature, therefore, systemic chemotherapy was given with palliative intent only. As a result, very poor survival outcomes were observed. But with the introduction of complete Cytoreductive surgery (CRS) and Hyperthermic intraperitoneal chemotherapy (HIPEC), the scenario has changed dramatically.

METHODOLOGY

An objective electronic database search was performed in Pubmed, NLM Catalog, Google scholar, Bookshelf, and Pubmed Central published in the time period from 2000 till 2020. All the randomized studies were included. In the absence of randomized studies, both prospective and retrospective studies were included. The outcomes of HIPEC were measured in terms of median survival, disease-free survival, overall survival, complications and drug toxicities.

RESULTS

CRS and HIPEC are considered the standard of care for PMP and MPM even in the absence of level 1 evidence due to lack of an effective alternative treatment. In colorectal and gastric cancer, several phase-three trials are showing overall survival benefit in selected cases while there is a prophylactic and palliative role of HIPEC in gastric cancer. Three reported phase 3 trials showed positive results in ovarian cancer. In peritoneal sarcomatosis, the role of HIPEC is yet to be proven.

CONCLUSION

The patient selection is the key to the successful outcomes after HIPEC. HIPEC should be performed by the experienced surgeons in specialized centres with a strong critical care and intensive care support to reduce the morbidity and mortality. Ongoing trials and future directions will prove to be an indispensable arm in the oncological armamentarium.

[Imaging of Mesentery and Omentum]

Although primary tumors in the mesentery and omentum are relatively rare, it is often necessary to distinguish them from other non-tumorous diseases. Since the omentum and mesentery are major routes for the spread of various abdominal diseases, the anatomy, type, and pattern of the diseases affecting these organs should be known in detail for accurate differential diagnosis. In addition, it is important to detect and promptly treat hidden lesions in the mesentery and omentum. Therefore, careful observation of the area where the lesion occur should be emphasized when assessing mesentery and omentum in abdominal CT.

From the Ronnett to the PSOGI Classification System for Pseudomyxoma Peritonei: A Validation Study

BACKGROUND

Several classifications have been used for pseudomyxoma peritonei (PMP), and among these, the Ronnett classification is the most commonly used. However, a new consensual Peritoneal Surface Oncology Group International (PSOGI) classification has recently been proposed. Nonetheless, to date, the ability of the PSOGI classification to predict survival based on its different disease histologic categories has not been validated.

METHODS

This study enrolled 117 patients with PMP who had undergone cytoreductive surgery and hyperthermic intraperitoneal chemotherapy (HIPEC) between 1997 and 2020. Cox proportional hazards regression models and time-dependent curve receiver operating characteristic (ROC) analyses were used to assess the predictive capacity of both classification systems for the overall survival (OS) and disease-free survival (DFS) of these patients.

RESULTS

Significant differences in the 5-year OS rate were found for the different histologic grades according to each of the classifications. The completeness of cytoreduction score (CCS) was identified as a factor that predicted patient OS prognosis (p = 0.006). According to the time-dependent ROC curves at the "100" time point, adjusted by the CCS and DFS, the capacity to predict OS was optimal and achieved an area under the curve (AUC) of about 69% for OS and approximately 62% for DFS.

CONCLUSIONS

Both the Ronnett and PSOGI classifications were able to predict survival optimally for this patient cohort. However, when the classifications were adjusted by the CCS, the predictive availability for OS was better with the PSOGI classification than with the Ronnett classification.

The Role of Hyperthermic Intraperitoneal Chemotherapy for Non-colorectal Peritoneal Surface Malignancies

BACKGROUND

Peritoneal carcinomatosis, from a variety of gastrointestinal and gynecological malignancies, has been historically challenging to treat and there remains a wide range of biologic aggressiveness in these patients. Malignancies commonly associated with PC include those of colorectal, appendiceal, gastric, ovarian, sarcoma, small intestinal, and primary peritoneal origin among others. Advances in our understanding of this unique disease process have led to significant interest in cytoreductive surgery and hyperthermic intraperitoneal chemotherapy (CRS-HIPEC) as an emerging treatment option. The goal of CRS-HIPEC is to remove all visible macroscopic disease while preserving organ function, and then treat microscopic disease through perfusion of the peritoneal cavity with heated chemotherapy.

PURPOSE

Although recent reviews have focused on the management of peritoneal carcinomatosis secondary to colorectal cancer given the publication of several recent randomized controlled trials, the purpose of the current review is to summarize the evidence on CRS-HIPEC for non-colorectal peritoneal surface malignancies, including appendiceal neoplasms, malignant peritoneal mesothelioma, gastric cancer, and ovarian cancer.

RESULTS

While retrospective studies have clarified the importance of prognostic factors such as the peritoneal carcinomatosis index, completeness of cytoreduction, histopathological characteristics, and lymph node positivity, the lack of convincing level 1 evidence for the use of CRS-HIPEC has led to it remaining a highly controversial topic.

CONCLUSION

The decision to utilize CRS-HIPEC should involve a multidisciplinary team approach and evaluation of prognostic factors to balance the short-term morbidity of the operation with maximum long-term benefits. Large, multi-institutional groups and ongoing trials hold promise for clarifying the role of CRS-HIPEC in peritoneal surface malignancies.

The Prognostic Impact of Pathology on Patients With Pseudomyxoma Peritonei Undergoing Debulking Surgery: A Systematic Review and Meta-Analysis of Retrospective Studies

Background: Pseudomyxoma peritonei (PMP) is a rare clinical condition with fatal outcomes, which is characterized by the progressive accumulation of mucinous ascites and peritoneal implants. Some studies have reported the effect of PMP biology on patient outcome. The objective of this study was to analyze published articles focusing on the impact of pathology on the prognosis of PMP patients undergoing debulking.

Methods: Data from all studies regarding the prognosis of patients, with different pathologies, who underwent debulking surgery were analyzed. We searched PubMed, the Wiley Online Library, Ovid, and the Cochrane Library (through January 2020). Studies were confined to those articles written in English. Five studies were identified, and the differences in 5-year survival rates were analyzed according to the Kaplan–Meier survival curves. The hazard ratios (HRs) of the 5-year survival rates were calculated.

Results: The mean and median 5-year survival rates of all patients were 39 and 40%, respectively. The median overall survival was 49.3 months. The mean 5-year survival rates of low-grade PMP was 45.2%. The five studies had sufficient data to calculate HRs from the 5-year survival rates data, and three had HRs lower than 1. The total HRs was 0.54, with a 95% CI between 0.33 and 0.89 (P = 0.01).

Conclusions: Among PMP patients receiving debulking surgery who are not able to undergo complete cytoreductive surgery, low-grade biological PMP had a better prognosis than high-grade PMP.

Experimental Treatment of Mucinous Peritoneal Metastases Using Patient-Derived Xenograft Models

Mucinous peritoneal metastases (PM) generally respond poorly to systemic treatment, and there is a clear unmet need for new treatment strategies to improve survival and quality of life for patients with PM. In this work, the growth inhibitory effect of five drugs (oxaliplatin (OXA; 5 mg/kg), irinotecan (IRI; 60 mg/kg), cabazitaxel (CBZ; 15 or 30 mg/kg), regorafenib (REG; 10, 30 or 60 mg/kg), and capecitabine (CAP; 359 or 755 mg/kg) was investigated in three orthotopic patient-derived xenograft models that mimic mucinous PM. Drugs were administered intraperitoneally (i.p.) as monotherapy weekly for 4 weeks (OXA, IRI), as one single i.p. injection (CBZ), or orally (REG, CAP) daily 5 of 7 days per week for four weeks, and i.p. tumor growth and survival were monitored and compared between treatment groups. The i.p. administered drugs (OXA, IRI, CBZ) had the strongest growth inhibitory effect, with OXA being most efficacious, completely inhibiting tumor growth in the majority of the animals. CBZ and IRI also strongly inhibited tumor growth, but with more variation in efficacy between the models. A moderate reduction in tumor growth was observed in all models treated with REG, while CAP had little to no growth inhibitory effect. Targeted next-generation-sequencing has identified mutational profiles typically associated with PM (mutations in KRAS, GNAS, and BRAF oncogenes), supporting the representativeness of the models. The results presented in this work support the continued exploration of i.p. treatment protocols for PM, with OXA remaining and CBZ emerging as particularly interesting candidates for further studies.

Pseudomyxoma Peritonei Originating from Transverse Colon Mucinous Adenocarcinoma: A Case Report and Literature Review

Background

Pseudomyxoma peritonei (PMP) is a rare neoplasm involving the peritoneum. Most PMPs are low-grade appendicular mucinous neoplasms (LAMNs). There have been no reports of PMP originating from a transverse colonic mucinous adenocarcinoma and causing metastatic mucinous adenocarcinoma. Case Presentation. We report a 46-year-old woman who presented with a right abdominal mass of more than 4-month duration. Transverse colonic mucinous adenocarcinoma, PMP, and ovarian metastatic mucinous adenocarcinoma were diagnosed. The patient's diet was normal, and she had no abdominal pain or bloating. The abdomen mass increased in the month before treatment. After chemotherapy, the transverse colon mass and ovarian giant cyst were resected and about 2000 mL of gelatinous tumor tissue was removed. Postoperative histology confirmed PMP from the transverse colonic mucinous adenocarcinoma, ovarian metastatic mucinous adenocarcinoma, and mesocolon metastatic cancer. Multiple lung metastases appeared 8 months after surgery. The patient died 29 months after surgery because of an inability to eat and poor nutrition. A systematic literature review of the management and outcome of all known similar cases is also presented.

Conclusions

This is the first report of PMP originating from a transverse colonic mucinous adenocarcinoma. It was diagnosed during resective surgery, involved ovarian metastasis, and survival was short. We did an extensive literature review in order to describe the clinical characteristics, histopathological findings, genetic profile, and potential treatments of PMP caused by nonappendiceal mucinous adenocarcinoma.

Defining "Complete Cytoreduction" After Cytoreductive Surgery and Hyperthermic Intraperitoneal Chemotherapy (CRS/HIPEC) for the Histopathologic Spectrum of Appendiceal Carcinomatosis

BACKGROUND

The completeness of cytoreduction (CC) score, which quantifies residual tumor, is a major prognostic factor when treating appendiceal carcinomatosis with cytoreductive surgery and hyperthermic intraperitoneal chemotherapy (CRS/HIPEC). Both CC-0 and CC-1 are considered complete cytoreductions (CC-0/1) and associated with the best outcomes. We analyzed if the CC-0/1 definition is reliable across appendiceal histopathologic subtypes.

METHODS

A prospective database of CRS/HIPEC patients with appendiceal carcinomatosis from 1998 to 2019 was reviewed to identify patients with CC-0/1. Kaplan-Meier overall survival (OS) and progression-free survival (PFS) by CC-score for each histopathology were calculated.

RESULTS

Overall, 297 patients had CC-0/1. Mean age was 54 ± 12 years with 67% females. Histopathologic subtypes were 45% low-grade mucinous carcinoma peritonei (LGMCP), 27% high-grade MCP (HGMCP), 20% HGMCP with signet ring cells (HGMCP-S), and 8% goblet cell adenocarcinoma (GCAC). CC-0 and CC-1 occurred in 57% and 43% of LGMCP, 65% and 35% of HGMCP, 68% and 32% of HGMCP-S, and 79% and 21% of GCAC, respectively. OS and PFS were statistically longer for CC-0 versus CC-1 in HGMCP-S (p = 0.001 and p = 0.005, respectively) and GCAC (p < 0.001 and p < 0.001), but not in LGMCP (p = 0.098 and p = 0.398) or HGMCP (p = 0.167 and p = 0.356).

CONCLUSIONS

Survival outcomes for CC-0 and CC-1 after CRS/HIPEC are different for HGMCP-S and GCAC but not for LGMCP and HGMCP. In HGCMP-S and GCAC, only CC-0 should be considered a complete cytoreduction and analyzed separately from CC-1. This distinction is key to understand disease behavior, accurately address patient prognosis, and explore new treatment strategies.

Proposed Classification of Pseudomyxoma Peritonei: Influence of Signet Ring Cells on Survival

The nomenclature and classification of pseudomyxoma peritonei (PMP) is confusing and controversial. Numerous classification systems have been proposed, none of which are easily reproducible or a useful guide for treatment. Patients with PMP of appendiceal origin were identified from our institution's database. Kaplan-Meier analyses were performed based on a proposed new PMP classification, a three-tiered grading system designated PMP1, PMP2, and PMP3. These results were compared with the established schemes by Ronnett and Bradley et al. There were 211 patients included in the analysis with a mean age of 51 ± 12 years at diagnosis. For PMP1, 86 patients (40.8%) included cases with abundant extracellular mucin and columnar non-stratified epithelium without dysplasia or atypia. For PMP3, 50 patients (23.7%) consisted of PMP with any percentage of signet ring cells (SRCs), For PMP2, 75 patients (35.5%) included all other patients. The mean age (± standard deviation) for PMP 1, 2, and 3 were 51 ± 12, 51 ± 12, and 51 ± 10 years, respectively ( P = 0.90). The three groups had similar sex distribution ( P = 0.24) and resection status ( P = 0.47). Kaplan-Meier analyses showed median survivals of 120, 88, and 40 months and 5-year survival rates of 85.7, 63.05, and 32.2 per cent ( P < 0.0001) for PMP 1, 2, and 3, respectively. Three distinct categories, PMP1, 2, and 3, were identified, which provide better stratification in terms of overall survival and represent differences in tumor biology that may impact treatment recommendations.

Should We Be Doing Cytoreductive Surgery with HIPEC for Signet Ring Cell Appendiceal Adenocarcinoma? A Study from the US HIPEC Collaborative

BACKGROUND

Appendiceal adenocarcinoma with signet ring cells (SCA) is associated with worse overall survival (OS), and it is unclear whether cytoreductive surgery with hyperthermic intraperitoneal chemotherapy (CRS-HIPEC) should be pursued in this patient population. We assessed the prognostic implications of signet ring cells in patients with appendiceal adenocarcinoma and peritoneal carcinomatosis undergoing CRS-HIPEC.

METHODS

The US HIPEC Collaborative, a 12-center, multi-institutional database of patients undergoing CRS-HIPEC, was reviewed for patients with SCA. Univariate and multivariate analyses were performed.

RESULTS

Of 514 patients undergoing CRS-HIPEC for appendiceal adenocarcinoma, 125 (24%) had SCA. The SCA and non-SCA groups had similar baseline characteristics. SCA had worse OS compared with non-SCA (32.0 vs 91.4 months, p < 0.001). In univariate analysis for only SCA cases, there was worse OS in patients with poorly differentiated tumors, positive lymph nodes, LVI, PCI > 20, or incomplete cytoreduction (CC-2/3). However, multivariate analysis showed only positive lymph nodes (HR 1.14 [95% CI 1.00-1.31], p = 0.04), poor differentiation (5.60 [1.29-24.39], p = 0.02), and incomplete cytoreduction (4.90 [1.11-12.70], p = 0.03) were independently associated with decreased OS for SCA.

CONCLUSION

While signet cells are a negative prognostic feature, they should not be a contraindication to CRS-HIPEC in patients with well-moderately differentiated tumors with negative lymph nodes, where complete cytoreduction can be achieved.

Efficacy of modified FOLFOX6 chemotherapy for patients with unresectable pseudomyxoma peritonei

Background

Pseudomyxoma peritonei (PMP) is a rare malignancy, and there is insufficient evidence about systemic chemotherapy for this disease.

Methods

We retrospectively evaluated the efficacy and safety of a chemotherapeutic regimen with 5-fluorouracil and oxaliplatin (modified FOLFOX6, mFOLFOX6) for patients with unresectable pseudomyxoma peritonei. Patients who received the therapy between April 2000 and February 2019 at the Department of Medical Oncology, Tohoku University Hospital, were enrolled in this study.

Results

Eight patients were treated with mFOLFOX6. The sites of primary tumor were appendix in six patients, ovary in a patient, and urachus in a patient. Six patients received surgery. Seven patients had histologically high-grade PMP, and one patient had low-grade PMP. The median follow-up duration was 27.2 months. All the patients had non-measurable regions as the targets of tumor response. Non-complete response or non-progressive disease was observed in seven patients, with a disease control rate of 87.5%. The median progression-free survival and overall survival were 13.0 months and 27.9 months, respectively. An obvious reduction in the symptoms was observed in two patients. Five patients experienced decline in the serum tumor markers, CEA or CA19-9. The grade 3/4 toxicity that was observed was grade 4 neutropenia in one patient and grade 3 neutropenia in two patients.

Conclusions

mFOLFOX6 might be an effective and tolerable treatment option for patients with unresectable PMP. To our knowledge, this is the first case series of mFOLFOX6 in patients with unresectable PMP and the first case series of systemic chemotherapy for Asian patients with unresectable PMP.

Electronic supplementary material

The online version of this article (10.1007/s10147-019-01592-x) contains supplementary material, which is available to authorized users.

Appendix-derived Pseudomyxoma Peritonei (PMP): Molecular Profiling Toward Treatment of a Rare Malignancy

OBJECTIVES

Pseudomyxoma peritonei (PMP) is a rare malignancy originating from the appendix, characterized by disseminated mucinous tumor implants on peritoneal surfaces. We examined the role of multiplatform molecular profiling to study biomarker-guided treatment strategies for this rare malignancy.

METHODS

A total of 54 patients with appendix-derived PMP were included in the study. Tests included one or more of the following: gene sequencing (Sanger or next generation sequencing), protein expression (immunohistochemistry), and gene amplification (C/fluorescent in situ hybridization).

RESULTS

Targeted sequencing of 47 genes detected variants in KRAS (81%), GNAS (74%), SMAD4 (16%), and ATM (16%). Mutations were found at low frequencies (n=1 to 2) in APC, BRAF, PIK3CA, MLH1, and TP53. GNAS and KRAS co-occurrence was found in 87%. Protein overexpression was found in epidermal growth factor receptor (83%), cyclooxygenase-2 (73%), cMET (63%), cKIT (58%), and platelet-derived growth factor receptor alpha (58%). Immune checkpoint expression was found in 36% (programmed cell death protein 1) and 18% (programmed death-ligand 1). Surrogate markers of cell proliferation were found at low rates (TLE3 23%, TOP2A 22%), consistent with the slow-growing biology of PMP. Phosophatase and tensin homolog was intact (wild type [100%]) and positive (immunohistochemistry [80%]). Patients exhibited stable microsatellite status and mismatch repair proficiency (93%). Importantly, multidrug resistance protein expression was elevated (100% BCRP, 94% MRP1, 88% PGP). Markers for gemcitabine (RRM1), fluorouracil (TS), oxaliplatin (ERCC1), and irinotecan (TOPO1) chemosensitivities were detected at favorable rates: 93%, 87%, 77% and 65%, respectively.

CONCLUSIONS

Molecular profiling by multiple platforms identified potential therapies for the nontargetable KRAS-mutated population. The role of cMET-targeted therapeutics and immune checkpoint inhibitors merits further investigation. Biomarker-guided selection of cytotoxic chemotherapies may facilitate efficacy to systemic treatment.

Discrimination of low- and high-grade appendiceal mucinous neoplasms by targeted sequencing of cancer-related variants

DNA was obtained from matching micro-dissected, primary tumor cells, paired metastases, and peripheral blood mononuclear cells (germline) from patients with appendiceal mucinous neoplasms. We compared specimens from patient cohorts comprising low-grade adenomucinous neoplasm versus high-grade mucinous adenocarcinoma using a targeted, amplicon sequencing panel of 409 cancer related genes (Ion Torrent Comprehensive Cancer Panel, Thermo-Fisher, Waltham, MA). Copy number variants, single nucleotide variants and small insertions/deletions were identified using a multiplex algorithm pipeline (GATK, VarScan2, MuTect2, SIFT, SIFT-INDEL, PolyPhen-2, Provean). There were significantly more damaging variants in high-grade versus low-grade tumor cohorts. Both cohorts contained damaging, heterozygous germline variants (catenin β1; notch receptor 1 and 4) in pathways associated with cell-lineage specification (WNT, NOTCH). Damaging, somatic KRAS proto-oncogene, GTPase mutations were present in both cohorts, while somatic GNAS complex locus mutations were confined to low-grade neoplasms. Variants predominantly affected transcription factors, kinases, and stem cell signaling molecules in canonical pathways including epithelial to mesenchymal transition, stem cell pluripotency, p53, PTEN, and NF-қB signaling pathways. High-grade tumors demonstrated MYC proto-oncogene, bHLH transcription factor (MYC) and death domain associated protein (DAXX) amplification and damaging somatic variants in tumor protein p53 (TP53), likely to amplify an aggressive phenotype. Damaging APC, WNT signaling pathway regulator (APC) deletions were identified in metastatic tissue of both cohorts suggesting a role in invasive disease. Our data suggest that germline dysregulation of WNT and/or NOTCH pathways predisposes patients toward a secretory cell phenotype (i.e., goblet-like cells) upon acquisition of somatic KRAS mutations. Additional somatically acquired variants activating oncogenes MYC and DAXX and inhibiting the critical tumor suppressor, tumor protein TP53, were consistent with manifestation of a high-grade phenotype. These additional changes within the epithelial to mesenchymal transition signaling network (WNT, NOTCH, RAS/ERK/PI3K, PTEN, NF-қB), produce aggressive high-grade tumor characteristics by actively driving cells towards dedifferentiation, proliferation, and migration.

Systemic chemotherapy before cytoreductive surgery and hyperthermic intraperitoneal chemotherapy (CRS/HIPEC) in patients with high-grade mucinous carcinoma peritonei of appendiceal origin

BACKGROUND

The role of systemic chemotherapy (SC) before cytoreductive surgery and hyperthermic intraperitoneal chemotherapy (CRS/HIPEC) in appendiceal high-grade mucinous carcinoma peritonei (HGMCP) is controversial. We analyzed the effect of SC prior to CRS/HIPEC in HGMCP.

METHODS

A prospective database of CRS/HIPEC procedures for HGMCP without signet ring cells and with signet ring cells (HGMCP-S) from 1998 to 2017 was reviewed. Exclusion criteria was prior surgery >5 regions or >2 regimens of prior SC. Perioperative variables were analyzed.

RESULTS

There were 140 HGMCP/HGMCP-S identified: 64 with prior SC (preSC) and 76 without (noSC). Groups were balanced for lymph node status, complete cytoreduction rate, disease burden, complications, and postoperative SC. PreSC had more HGMCP-S, moderately/poorly differentiated histology, and longer time-to-surgery (median: 6 vs 2 months, p < 0.001). Median overall survival (mOS) was 40 vs 86 and median progression-free survival (mPFS) was 19 vs 43 months for preSC vs noSC, respectively (p = 0.006 and p = 0.007). In HGMCP-S subanalysis, mOS was 25 vs 39 and mPFS 16 vs 29 months for preSC vs noSC, respectively (p = 0.188 and p = 0.063). In moderately/poorly differentiated histology subanalysis, mOS was 38 vs 56 and mPFS 18 vs 29 months in preSC vs noSC, respectively (p = 0.199 and 0.082). Prior SC was not linked to improved OS or PFS in non-signet ring HGMCP or well-differentiated histology subanalysis.

CONCLUSION

Prior SC was not associated with less disease burden, better cytoreduction rates, or improved clinical outcomes in HGMCP, regardless of histopathologic subtype. Traditional SC agents may not be effective in HGMCP in the neoadjuvant setting.

Pseudomyxoma peritonei induced by low-grade appendiceal mucinous neoplasm accompanied by rectal cancer: a case report and literature review

Background

Pseudomyxoma peritonei (PMP) is a disease involving the peritoneum characterized by the production of large quantities of mucinous ascites. PMP has a low incidence, is difficult to diagnose, and has a guarded prognosis. PMP induced by low-grade appendiceal mucinous neoplasm is extremely rare, and PMP accompanied by rectal cancer is even rarer.

Case presentation

We present a unique case of a 70-year-old male with PMP induced by low-grade appendiceal mucinous neoplasm accompanied by rectal cancer. The patient’s clinical, surgical, and histologic data were reviewed. The patient had persistent distended abdominal pain without radiating lower back pain, abdominal distension for 1 month, and no exhaustion or defecation for 4 days. A transabdominal ultrasound-guided biopsy was performed on the first day. The patient received an emergency exploratory laparotomy because of increased abdominal pressure. We performed cytoreductive surgery, enterolysis, intestinal decompression, special tumour treatment and radical resection of rectal carcinoma. The postoperative course was uneventful. The postoperative histological diagnoses were PMP, low-grade appendiceal mucinous neoplasm and rectal medium differentiated adenocarcinoma. At the 1-year follow-up visit, no tumour recurrence was observed by computed tomography (CT). We also performed a literature review.

Conclusions

We should be aware that PMP can rarely be accompanied by rectal cancer, which represents an easily missed diagnosis and increases the difficulty of diagnosis and treatment. Additionally, there are some typical characteristics of PMP with respect to diagnosis and treatment.

An assessment of the survival impact of multimodal anesthesia/analgesia technique in adults undergoing cytoreductive surgery with hyperthermic intraperitoneal chemotherapy: a propensity score matched analysis

BACKGROUND

Studies suggest volatile anesthetics and opioids may enhance the malignant potential of cancer cells. The objective of this single institution retrospective study was to evaluate the survival impact of a multimodal opioid-sparing nonvolatile anesthetic technique (MA) in a group of patients who had undergone cytoreductive surgery with hyperthermic intraperitoneal chemotherapy (CRS-HIPEC) for appendiceal carcinomatosis.

METHODS

Propensity score matching (PSM) and Cox proportional hazard models were used to compare the survivals of patients who received MA (MA group), to those who received volatile-opioid anesthesia (volatile-opioid group).

RESULTS

Of the 373 patients, 110 (29%) were in the MA group and 263 (71%) in the volatile-opioid group. The MA group was older (mean ± standard deviation (SD): 55 ± 11 versus 53 ± 10 years, p = .035) and had more patients with ASA scores 3 or 4 (90% versus 81%, p = .032), and those with high grade tumors (18% versus 12%, p = .009). Intraoperative opioid consumption was lower in the MA group (mean morphine equivalents ± SD: 13 ± 10 versus 194 ± 789, p < .0001). After PSM, 107 patients remained in each group. In the adjusted Cox proportional hazards model after PSM, MA was not associated with improved progression free survival (PFS) (HR 1.45, 95% CI [0.94-2.22], p = .093) or overall survival (OS) (HR 1.66, 95% CI [0.86-3.20], p = .128), when compared to volatile-opioid anesthesia.

CONCLUSIONS

In this retrospective study, a multimodal opioid-sparing nonvolatile anesthetic approach was not associated with improved survival. Precis' statement: In this study of patients undergoing major cancer surgery, the use of multimodal anesthetic and analgesic agents, while avoiding volatile anesthetics and minimizing opioid use was not associated with improved survival.

[Recurrence of pseudomyxoma peritonei with liver and splenic metastases: about a case and literature review]

Le pseudo myxome péritonéal (PMP), est un syndrome clinicopathologique caractérisé par une ascite mucineuse et des pools de mucine comportant un épithélium mucineux néoplasique dans la cavité péritonéale. Le PMP est peu fréquent, et se présente avec des manifestations cliniques et pathologiques inhabituelles posant des problèmes diagnostic et thérapeutiques. L'atteinte des viscères abdominaux et les métastases ganglionnaires sont rares et se limitent à des cas sporadiques rapportes dans la littérature. Nous rapportons ici le cas d'un patient de 56 ans opéré à deux reprises pour PMP d'origine appendiculaire, et qui a consulté pour douleurs abdominales évolutives, cinque ans après sa dernière cure. Le scanner avait objective une récidive de pseudo myxome péritonéal, avec présence de lésions intraparenchymateuses spléniques et hépatique .l 'étude anatomopathologique avait objective la récidive d'un pseudo myxome péritonéal de bas grade avec la localisation intrasplénique et hépatique des mêmes lésions histologiques confirmant les métastases.

Outcomes in Peritoneal Dissemination from Signet Ring Cell Carcinoma of the Appendix Treated with Cytoreductive Surgery and Hyperthermic Intraperitoneal Chemotherapy

BACKGROUND

Cytoreductive surgery and hyperthermic intraperitoneal chemotherapy (CRS/HIPEC) is standard treatment for peritoneal dissemination from appendiceal cancer (AC); however, its role in high-grade histopathologic subtypes (high-grade mucinous carcinoma peritonei [HGMCP] and HGMCP with signet ring cells [HGMCP-S]) is controversial due to their aggressive behavior. This study analyzed clinical outcomes of high-grade AC after CRS/HIPEC.

METHODS

A prospective database of CRS/HIPEC procedures for HGMCP performed from 1998-2017 was reviewed. Perioperative variables and survival were analyzed.

RESULTS

Eighty-six HGMCP and 65 HGMCP-S were identified. HGMCP had more positive tumor markers (TM) (CEA/CA-125/CA-19-9) than HGMCP-S (63% vs 40%, p = 0.005). HGMCP had higher Peritoneal Cancer Index (32 vs 26, p = 0.097) and was less likely to have positive lymph nodes (LN) than HGMCP-S (28% vs 69%, p = < 0.001). Complete cytoreduction was achieved in 84% and 83%, respectively. PFS at 3- and 5-years was 59% and 48% for HGMCP vs 31% and 14% for HGMCP-S. Median PFS was 4.3 and 1.6 years, respectively (p < 0.001). OS at 3- and 5-years was 84% and 64% in HGMCP vs 38% and 25% in HGMCP-S. Median OS was 7.5 and 2.2 years, respectively (p < 0.001). LN negative HGMCP-S had longer median PFS and OS than LN positive HGMCP-S (PFS: 3.4 vs 1.5 years, p = 0.03; OS: 5.6 vs 2.1 months, p = 0.021).

CONCLUSIONS

The aggressive histology of HGMCP-S is associated with poor OS, has fewer abnormal TM, and is more likely to have positive LN. However, CRS/HIPEC can achieve a 5-year survival of 25%, which may improve to 51% with negative LN.

Long term survival analysis after hyperthermic intraperitoneal chemotherapy with oxaliplatin as a treatment for appendiceal peritoneal carcinomatosis

BACKGROUND AND OBJECTIVES

Complete cytoreductive surgery (CRS) followed by hyperthermic intraperitoneal chemotherapy (HIPEC) have been proven to lengthen survival in appendiceal peritoneal carcinomatosis (PC-A). The aim of this study was to analyze survival results of this therapy in our institution over the last 10 years.

METHODS

Data was retrospectively reviewed and analyzed. Treatment consisted of CRS plus HIPEC with oxaliplatin. Ronnett's histologic classification was used (peritoneal mucinous carcinomatosis (PMCA), PMCA with intermediate features (PMCA-I) and disseminated peritoneal adenomucinosis (DPAM)). Overall survival (OS) and disease-free survival (DFS) estimates were calculated using Kaplan-Meier survival curves.

RESULTS

109 patients with PC-A underwent laparotomy with curative intent. Of those, 92 underwent CRS plus HIPEC. Median follow-up was 42 months. The 5 and 10-year OS rates for the HIPEC group were 82.2% and 76.5%. The 5 and 10-year OS estimates for DPAM and PMCA-I subgroups were 100% and 100%, 78.1% and 72.9%, respectively. For the PMCA subgroup, the 3 and 5-year OS were 61.4% and 40.1%, respectively. The 5 and 10-year DFS estimates were 71.9% and 42.7%.

CONCLUSION

CRS plus HIPEC with oxaliplatin represent an effective therapeutic approach for PC-A. Long term OS estimates for patients treated at our institution are encouraging.

Pseudomyxoma pleurii and peritonei secondary to sigmoid colon adenocarcinoma: a rare clinico-pathologico-radiological presentation

Pseudomyxoma peritonei (PMP) is a rare condition resulting from mucin-producing tumors that have disseminated into intraperitoneal implants and mucinous ascites. The extra-abdominal spread of PMP is exceptionally rare, with few reported cases in the medical literature. Pseudomyxoma pleurii is an infrequently encountered clinical syndrome characterized by transdiaphragmatic pleural extension and spread of PMP. The disease is highly fatal. We hereby report a case of 58 years old woman who presented with an abdominal distension and shortness of breath of 2 months duration. Histopathology confirmed the diagnosis of large mucin-producing rectosigmoid adenomatous polypoid lesion with malignant transformation and PMP that had spread to the right pleural space. PMP from colon tumor is uncommon and its transdiaphragmatic pleural extension is very unusual complicated by management challenge and high mortality rate.

Unusual case of intraluminal cecal recurrence of a low grade appendiceal mucinous neoplasm (LAMN)-Case report and brief literature review

•

Penetration of the visceral peritoneum by a mucinous neoplasm consists the cardinal point in the management and prognosis.

•

Patients with LAMN confined to the muscularis propria after histologic examination of the entire appendix (pTis) have essentially no risk of recurrence.

•

There are no clear guidelines regarding appropriate management of appendiceal LAMNs with positive margins, especially when confined within the serosa.

•

A simple cecectomy is traditionally suggested by some authors, but according to more recent data its necessity is debated.

•

LAMN may rarely recur in the form of a polypoid protrusion into the cecal lumen and this may originate from the buried stump of the appendix on the ground of a positive margin.

Introduction

Appendiceal mucinous neoplasms exhibit a wide spectrum of clinical behavior, ranging from neoplasms which are relatively slow-growing but with considerable risk for recurrence and eventual death and those neoplasms that are highly aggressive with increased likelihood of early death. Clinical behavior depend mainly on mucinous neoplasms grading and staging.

Presentation of case

We present the incidental finding of a mucinous appendiceal neoplasm in a 52 years old woman during her follow up for an operated breast carcinoma. The patient underwent appendectomy and a low grade appendiceal mucinous neoplasm (LAMN) confined into the appendiceal wall was diagnosed. Resection margin showed fibrous replacement of the appendiceal wall and some acellular intraluminal mucin. Three months later the tumor recurred inside the cecal lumen and a right hemicolectomy was performed showing again a LAMN confined into the bowel wall.

Discussion

According to the latest AJCC eighth edition patients with pTis LAMN, as in our case, (LAMN confined to the muscularis propria after histologic examination of the entire appendix) have essentially no risk of recurrence. Moreover, some authors suggest follow up for LAMN confined into the appendix even with a positive surgical margin.

Conclusion

Rarely, LAMN may recur in the form of a polypoid protrusion into the cecal lumen and this recurrence may originate from the buried stump of the appendix, especially when the surgical margin is positive.

Can low grade PMP be divided into prognostically distinct subgroups based on histological features? A retrospective study and the importance of using the appropriate classification

INTRODUCTION

The pathological classification of PMP of appendiceal origin has prognostic and treatment implications. Our goals were to • Classify low grade mucinous carcinoma peritonei (LGMCP) into prognostically distinct subgroups based on histological features. • Compare the reproducibility of the WHO and the PSOGI classifications for both PMP and the appendiceal primary tumor.

PATIENTS AND METHODS

A retrospective analysis of patients undergoing CRS and HIPEC or debulking surgery was done. All the tumors were re-classified according to the PSOGI classification. LGMCP was further classified into three histological subgroups and the impact on survival was evaluated.

RESULTS

From Jun 2011 to June 2016, 101 patients underwent CRS with HIPEC (n = 89) or debulking surgery (n=12). The median PCI was 28 (3-39) and 74.1% patients had CC-0/1 resections. Of the 76.2% patients who had LGMCP, 4 patients (5.1%) were classified as group 1, 54 (70.1%) as group 2 and 19 patients (24.6%) as group 3. At a median follow up of 21 months, the disease free survival was not reached, 30 months and 14 months for groups 1, 2 and 3 respectively (p = 0.09). There was no difference in overall survival. Using the WHO classification, there was a discordance in the grade of the primary tumor and the peritoneal lesions in 19.8% and conflicting terminology was used in 62% of patients.

CONCLUSIONS

The subgroups of LGMCP described here are prognostically different though this needs further prospective evaluation in larger series. The PSOGI classification is more uniformly reproducible and should be preferred to the WHO classification.

An Update on the Diagnosis, Grading, and Staging of Appendiceal Mucinous Neoplasms

Despite advances in our understanding of appendiceal mucinous neoplasms and their relationship to the pseudomyxoma peritonei syndrome, the classification of mucinous tumors of the appendix is still confusing. This review will provide an update on the various classification systems that have been recently proposed for appendiceal mucinous neoplasia, with a particular emphasis on how to handle and report the histologic findings for these tumors using the newly published Peritoneal Surface Oncology Group International (PSOGI) and American Joint Committee on Cancer (AJCC) eighth edition guidelines. A simplified approach to diagnostic reporting of appendiceal mucinous neoplasms based on the 3-tier AJCC grading scheme is detailed and specific criteria for assessing grade in appendiceal mucinous neoplasia will be outlined. In addition, histologic mimics of appendiceal mucinous neoplasia and how to distinguish these mimics from mucinous neoplasia will be discussed. Finally, despite improvements in diagnostic terminology, significant challenges in classifying appendiceal mucinous neoplasia persist and diagnostic strategies will be detailed to assist practicing pathologists in these challenging scenarios.

Incidence and Survival of Appendiceal Mucinous Neoplasms: A SEER Analysis

OBJECTIVES

The aim of this study is to characterize the changes in the incidence, presentation, surgical treatment, and survival of patients with appendiceal mucinous neoplasm (AMN) over the past 4 decades using nationwide cancer surveillance data.

METHODS

Patients with the diagnosis of AMN were identified in the Surveillance Epidemiology and End Results (SEER) database. Information on demographics, disease characteristics, and surgical treatment was collected. Temporal changes in AMN incidence, characteristics of cases, and survival were analyzed from 1973 to 2011. Determinants of overall survival (OS) were examined using both crude and multivariable Cox proportional hazard models.

RESULTS

The overall incidence rate of AMN increased on average 3.1%/1,000,000 persons-years (P<0.001). A significant decline in the age at diagnosis was observed (P=0.014). The proportion of patients presenting with distant disease at diagnosis also significantly increased (P=0.004). Five-year survival of patients with distant stage AMN increased at a rate of 3.5%/y between 1984 and 2006 (P<0.001). Median OS was not reached for localized and regional stage disease. Median OS for distant stage disease was 42 months.

CONCLUSIONS

There has been an increase in the overall incidence of AMN with an observed increase in the proportion of younger age and distant stage at diagnosis. The OS has improved over time.

Repeat cytoreduction and hyperthermic intraperitoneal chemotherapy for recurrent peritoneal carcinomatosis of appendiceal origin

BACKGROUND

The purpose of this study was to clarify the role of repeat cytoreductive surgery and hyperthermic intraperitoneal chemotherapy (CRS + HIPEC) in the management of recurrent peritoneal carcinomatosis of appendiceal origin.

METHODS

Data were retrieved on 42 patients who underwent CRS + HIPEC; 29 repeat surgical procedures were performed in 13 patients.

RESULTS

Complete cytoreduction was achieved in 12 of 13 patients by the second CRS. Repeat recurrence was detected in 11 patients, eight of whom underwent a third CRS. The peritoneal cancer index decreased from initial CRS to repeat CRS but was still higher than 18 in nine patients at the second CRS. Preoperative chemotherapy was given to three patients with early recurrence. Grade 3-5 morbidity and 90-day mortality were not significantly different between initial and repeat CRS. Five-year survival rates after first and second CRS were 75.5 and 67.7%, respectively. Complete cytoreduction at second CRS was a significant prognostic factor. Among patients with recurrence after the second CRS, patients who underwent a third CRS showed a better prognosis than those who did not.

CONCLUSIONS

Repeat CRS is oncologically beneficial, and the morbidity rate was as high as that of initial CRS. Complete cytoreduction was the key to successful long-term results. Although further recurrence was common, aggressive resection was useful, even in cases of diffuse recurrence.

Impact of Cellularity on Oncologic Outcomes Following Cytoreductive Surgery and Hyperthermic Intraperitoneal Chemoperfusion for Pseudomyxoma Peritonei

BACKGROUND

The Peritoneal Surface Oncology Group International (PSOGI) recommends pathologic reporting of tumor cellularity in patients with pseudomyxoma peritonei (PMP) undergoing cytoreductive surgery and hyperthermic intraperitoneal chemoperfusion (CRS-HIPEC). We investigated the prognostic significance of PMP cellularity, or lack thereof (acellular mucin), following CRS-HIPEC.

METHODS

We reviewed clinical data for 310 CRS-HIPEC procedures in low-grade (American Joint Committee on Cancer grade G1) PMP with acellular mucin (n = 19), scant cellularity (n = 30), or moderate cellularity (n = 242). Kaplan-Meier survival curves and multivariate Cox regression models identified prognostic factors affecting oncologic outcomes.

RESULTS

Compared with patients with acellular mucin, those with scant and moderate cellularity had higher PCI and less-frequent complete macroscopic resection. After an estimated median follow-up of 49 months, 4 patients (14%) with scant cellularity and 127 patients (56%) with moderate cellularity progressed, while none of the patients with acellular mucin progressed. While the median progression-free survival (PFS) was not reached for patients with acellular mucin or scant cellularity (estimated 5-year PFS probability of 100 and 83%, respectively), patients with moderate cellularity demonstrated a median PFS of 32 months (estimated 5-year PFS probability of 27%). In a multivariate model, degree of disease cellularity, or lack thereof (acellular mucin), was an independent predictor of PFS but not overall survival.

CONCLUSIONS

Early disease progression is unlikely in patients with acellular mucin undergoing CRS-HIPEC, as opposed to a 14% recurrence rate with scant cellularity. Thorough pathologic assessment for cellularity, or lack thereof (acellular mucin), is vital for accurate prognostication of disease progression for patients with low-grade PMP undergoing CRS-HIPEC.

Incidental appendectomy during robotic laparoscopic prostatectomy-safe and worth to perform?

PURPOSE

The purpose of this study is to investigate the safety and patients' benefit of incidental appendectomy during robot-assisted laparoscopic radical prostatectomy (RALRP).

METHODS

Fifty-three patients, who had incidental appendectomy during RALRP between January 2012 and March 2014, were enrolled to this study. To evaluate the safety of the procedure, following parameters were evaluated: patient age, duration of surgery, perioperative complications (classified by Clavien-Dindo), time to bowel movement, and length of hospital stay. Furthermore, intraoperative visual appearance, location, and histopathological evaluation of the appendix were evaluated. Data was analyzed by descriptive statistics.

RESULTS

Mean age of patients was 61 years, the average hospital stay 5 days. No perioperative complications occurred. The appendix was unsuspicious in 39 patients (73.6%); 14 patients (26.4%) had macroscopically signs of inflammation. Of the 53 resected appendixes, the histopathological evaluation showed 33 (62.2%) inconspicuous appendices, 11 (20.8%) post-inflammatory changes, 4 (7.5%) with chronical signs of inflammation and 3 (5.7%) with signs of acute inflammation. In 2 patients (3.8%), low-grade mucinous neoplasms were found in the specimens.

CONCLUSIONS

Incidental appendectomy during RALRP is a feasible procedure. With regard to inflammation and neoplastic changes, incidental appendectomy can be considered for patients scheduled for robot-assisted prostate surgery.

Cytoreductive surgery and hyperthermic intraperitoneal chemotherapy in the management of pseudomyxoma peritonei: A single-center experience

BACKGROUND AND AIMS

Pseudomyxoma peritonei (PMP) results from perforated appendiceal tumors. It is usually diagnosed preoperatively by imaging. Cytoreductive surgery (CRS) and hyperthermic intraperitoneal chemotherapy (HIPEC), although aggressive long procedure with high complications rate, was considered the optimal treatment. This study is aiming to study the role of CRS and HIPEC in the management of PMP and assess the outcome.

METHODS

This is a retrospective study which was conducted at King Faisal Hospital and Research Center, a tertiary care hospital during the period from November 2008 to June 2016. Approval of the Research Advisory Council was obtained. Forty-one procedures of CRS and HIPEC were performed in 38 patients. Using the open abdomen technique, CRS was performed using standard peritonectomy procedures and visceral resections directed toward the complete elimination of tumors from abdominopelvic cavity. HIPEC was performed using mitomycin C in a dose of 30 mg/m² and allowed to circulate in abdominopelvic cavity for 90 min at 41.0 to 42.2 °C.

RESULTS

Forty-one procedures were performed in 38 patients. Three procedures were done as repeat CRS and HIPEC. No perioperative mortality. Cystoscopy and bilateral ureteric stents in 35 procedures (85.5%). Hospital stay (range 9-85 days) average is 21 days. Follow up period is 1-84 months, and median follow up is 54 months. Five-year survival rate is 92%. Median 5-year disease-free survival rate is 60%. Two patients died during the follow up period by septic shock and one patient died from disease progression.

CONCLUSION

CRS and HIPEC is well-tolerated and feasible management for PMP.

Grading and staging mucinous neoplasms of the appendix: a case series and review of the literature

The grading and staging of appendiceal mucinous neoplasms is challenging and fraught with terminology problems, but has critical prognostic and therapeutic implications. We utilized a small case series to examine the grading and staging systems of appendiceal mucinous neoplasms and outline the evidence for the new systems proposed in the upcoming 8th edition of the American Joint Committee on Cancer (AJCC) Staging Manual. We reviewed 33 cases of appendiceal mucinous neoplasms with available clinical follow-up data, 6 of which were widely disseminated in the peritoneum. An additional 4 cases with disseminated peritoneal involvement were also reviewed. A detailed review of the literature was performed with an emphasis on features associated with disease recurrence and correlation of grade with outcome. Recurrence was not seen in 64 low-grade appendiceal mucinous neoplasms (LAMNs) confined to the muscularis propria in our series (n=21) or in the literature (n=43). Of cases of LAMN with neoplastic epithelium present beyond the muscularis propria, 64% (57/89) had peritoneal disease at the time of diagnosis or follow-up. A majority of studies of disseminated appendiceal mucinous neoplasms showed significant five-year survival differences using a three-tier grading scheme. Thus, LAMNs confined to the muscularis propria are best considered as in situ tumors, as these are cured with complete excision. A three-tier system has prognostic significance and should be used for grading of disseminated appendiceal mucinous neoplasms. The conclusions of this case series and literature review provide evidence to support the changes proposed in the 8th edition of the AJCC Staging Manual.

The histopathological classification, diagnosis and differential diagnosis of mucinous appendiceal neoplasms, appendiceal adenocarcinomas and pseudomyxoma peritonei

The vermiform appendix is the primary site of several distinctive benign and malignant neoplasms. Some can produce the clinical syndrome of pseudomyxoma peritonei (PMP). A consensus on their terminology was reached by an international panel of pathologists and clinicians working under the auspices of the Peritoneal Surface Oncology Group International (PSOGI), and this review discusses the application of the PSOGI classification to routine reporting. We discuss diagnosis and differential diagnosis together with implications for patient management, covering low-grade appendiceal mucinous neoplasms, high-grade appendiceal mucinous neoplasms, serrated polyps, adenomas and adenocarcinomas. We do not cover goblet cell tumours or neuroendocrine neoplasms in this paper.

Palliative Radiation Therapy for Symptom Control in an Advanced Case of Pseudomyxoma Peritonei

Pseudomyxoma peritonei (PP) is a rare clinical condition characterized by progressive mucinous ascites, which is typically caused by a mucin-producing neoplasm. Reports of radiation therapy (RT) in the management of PP are limited. We report a unique case of a 62-year-old woman with severe, end-stage, recurrent PP and a large, mucin-secreting mass protruding through her abdominal wall. Low-dose, hypofractionated palliative RT was administered for symptom control with the hope of improving her quality of life. We suggest that radiation therapy be considered in the comprehensive palliative management of patients with PP.