Management and prognosis of low-grade appendiceal mucinous neoplasms: A clinicopathologic analysis of 50 cases

Incidental appendiceal mucocele discovery: A case series and literature review

INTRODUCTION

Low-grade appendiceal mucinous neoplasms (LAMNs) are rare entities that can present significant challenges when discovered incidentally by general surgeons during surgery or through postoperative pathology. These lesions may mimic common abdominal conditions and are often not suspected preoperatively.

METHODS

We present a case series of five patients in whom appendiceal mucoceles were incidentally identified either intraoperatively or on postoperative pathological examination. The patients ranged from 36 to 79 years old and presented with symptoms such as right lower quadrant pain, initially attributed to appendicitis, ovarian torsion, or other gynecological conditions. Intraoperative findings varied from dilated appendices with mucinous content to large cystic masses involving adjacent structures.

RESULTS

In each case, the general surgeon had to make immediate decisions regarding management. Surgical interventions included laparoscopic appendectomy and open right hemicolectomy, with an emphasis on careful handling to prevent rupture and spillage of mucin. Postoperative pathology confirmed LAMNs, with tumor stages ranging from pTis to pT4a. Some patients required additional procedures, such as cytoreductive surgery with hyperthermic intraperitoneal chemotherapy (HIPEC), due to the presence of acellular mucin or peritoneal involvement. The discussion focuses on practical guidance for general surgeons when faced with an incidental appendiceal mucocele. Key recommendations include avoiding intraoperative rupture by gentle handling, assessing the need for extended resection based on intraoperative findings, and ensuring thorough communication with pathology for accurate staging. Postoperative management should involve reviewing pathology reports carefully, considering referral to a multidisciplinary team for higher-stage tumors, and implementing long-term surveillance protocols due to the risk of recurrence.

CONCLUSION

General surgeons play a critical role in the initial management of incidentally discovered appendiceal mucoceles. Prompt recognition and appropriate intraoperative decision-making are essential to optimize patient outcomes. By adhering to careful surgical techniques and collaborating with multidisciplinary teams, surgeons can effectively manage these unexpected findings and mitigate potential complications associated with LAMNs.

A scoping review of postoperative surveillance strategies for localized, low-grade appendiceal mucinous neoplasms

INTRODUCTION

There is a paucity of data to support surveillance protocols for localized, low-grade appendiceal mucinous neoplasms (LAMNs) after resection.

METHODS

A search strategy was developed to identify postoperative surveillance strategies for LAMNs, in the context of rates of recurrence and disease-free survival, and applied to four literature databases. Resultant citations were subject to screening in duplicate, in three stages: title, abstract, and full-text. Data was extracted from the final set of included articles and subject to descriptive statistics.

RESULTS

A total of 16 articles, representing 1218 patients, were included. The duration of surveillance ranged from 0.1 to 294 months, and the mode surveillance interval was three months. The most common surveillance method was imaging (n ​= ​610 patients, 48.7 ​%). Thirty one patients had disease recurrence (2.7 ​%). Time to recurrence ranged from 2.5 to 68 months, and the range of five-year survival was 93.5-95.2 ​% among five studies.

DISCUSSION

In the absence of strong evidence to suggest that surveillance confers a survival benefit for patients with localized LAMNs after resection, decisions about surveillance should be patient-oriented.

Outcomes of laparoscopic single-incision caecal pole resection for low-grade appendiceal mucinous neoplasm

INTRODUCTION

Low-grade appendiceal mucinous neoplasm (LAMN) is a rare disease, and its clinical course varies from an incidental finding without symptoms to pseudomyxoma peritonei. Furthermore, there are few established treatment guidelines. This study was designed to confirm the outcomes in patients diagnosed with LAMN who underwent single-incision laparoscopic caecal pole resection.

PATIENTS AND METHODS

This study was conducted on pathologically confirmed LAMNs from patients who underwent surgery at a single centre, a tertiary institution, from July 2016 to August 2022. Patients diagnosed with LAMN as a result of biopsy were included. All surgeries were performed with single-incision laparoscopic caecal pole resection by a single surgeon.

RESULTS

A total of 70 patients were included. The median age was 65.5 years and 36 (51.4%) patients were female. The baseline carcinoembryonic antigen (CEA) was 8.08 ng/mL (0.76-148.11). The mean maximum diameter was 29.4 mm (7-70) and calcification was seen in 22 cases on pre-operative computed tomography (CT). As a result of histological examination, all patients were marginally negative. The larger the tumour size, the higher the CEA was ( P = 0.011), and it was often accompanied by calcification ( P = 0.021). In addition, tumour size and CEA showed a positive partial correlation with each other ( r = 0.318, P = 0.018). The overall median follow-up period was 22.7 months (2-60). One case had suspected of recurrence on CT scan performed at 33 months following the surgery, but there were no related symptoms.

CONCLUSION

Single-port laparoscopic caecal pole resection without margin involvement in LAMN was safe and feasible, and showed a favourable long-term outcome.

Low back pain as main symptom in Low-grade Appendiceal Mucinous Neoplasm (LAMN): A case report

BACKGROUND

Low back pain is the leading cause of disability worldwide. It is also the main cause of the limitation of activities and absence from work in much of the world and a cause of great economic burden. The greatest percentage of low back pain is classified as nonspecific (i.e. not attributable to a defined pathology), while the others may concern specific pathologies of the lumbar region or suggest pathologies of non-musculoskeletal origin. Consequently, evaluating any signs and symptoms mimicking musculoskeletal conditions is crucial.

CASE DESCRIPTION

This case report describes a 64-year-old female patient who first presented to the physiotherapist with two weeks of low back pain, complaining of a different clinical presentation than the previous episodes. The patient's pain started spontaneously and was located in the lumbar region over a diffuse area. Symptoms were constant throughout the day and did not change with movement. Based on the examination findings, the physiotherapist decided to make an urgent referral to the patient's General Practitioner.

OUTCOMES

Following ultrasound examination and Computed Tomography scan, an 8.5 cm mass was confirmed in the abdominal region. It was surgically removed, and a histological diagnosis of Low-grade Appendiceal Mucinous Neoplasm (LAMN) was made.

CONCLUSION

The physiotherapist's evaluation and decision-making process was fundamental in the patient's referral due to suspected pathology not within the scope of practice. This revealed a rare condition, which, according to the existing literature, is usually diagnosed in the event of collateral imaging findings or upon presentation of complex and/or emergency clinical pictures.

Low-grade appendiceal mucinous neoplasm: A case report

RATIONALE

Low-grade appendiceal mucinous neoplasm (LAMN) is a clinically rare tumor that predominantly occurs in females and presents with nonspecific symptoms, often resulting in misdiagnosis. While postoperative pathology remains the gold standard for diagnosis, accurate preoperative identification through various diagnostic methods is essential for effective treatment planning. To raise awareness of this condition, we present a case of a middle-aged male diagnosed with LAMN.

PATIENT CONCERNS

A 52-year-old male presented to outpatient clinic with right lower abdominal pain lasting 1 day. He described the pain as continuous cramping, exacerbated by movement and coughing, with associated nausea.

DIAGNOSIS

Physical examination revealed tenderness in the right lower quadrant and a palpable mass measuring approximately 6.5 cm × 5.0 cm, with poor definition and limited mobility. An elevated white blood cell count (16.2 × 109/L) and a mixed cystic and solid mass were noted, prompting admission for further evaluation. Further, abdominal enhanced computed tomography revealed a mixed-density lesion in the right ileocecal region, measuring approximately 6.5 cm × 5.0 cm. This finding was suggestive of an appendiceal mucinous neoplasm, with mucinous adenocarcinoma remaining a possibility that could not be excluded.

INTERVENTIONS

The patient underwent a laparoscopic right hemicolectomy on June 5, 2024, and the gross specimen showed: a 6.5 cm × 5.0 cm mass was found in the appendix area on the surface of the intestinal tube, a large amount of jelly was found after incision, and the mass was connected to the intestinal cavity.

OUTCOMES

The patient recovered well after surgery, the abdominal drainage tube was pulled out on the 8th day after surgery, and the patient was discharged on the 13th day after surgery. Postoperative examination showed LAMN and mucus accumulation in the wall of the appendix with a foreign body giant cell reaction, acute attack of chronic appendicitis, and suppurative inflammation with peripheral inflammation. Postoperative diagnosis: LAMN; acute chronic appendicitis attack.

LESSONS

As a rare clinical gastrointestinal tumor, LAMN lacks specific clinical manifestations, and its diagnosis depends on postoperative examination; however, the indications for surgery are clear and the clinical prognosis is good. The key to surgery is to protect the tumor body to avoid rupture and cause the development of peritoneal pseudomyxoma (PMP).

Diagnostic difficulties in the differentiation between an ovarian metastatic low‑grade appendiceal mucinous neoplasm and primary ovarian mucinous cancer: A case report and literature review

Low-grade appendiceal mucinous neoplasm (LAMN) is a tumor that primarily originates from the appendix and belongs to the family of appendiceal mucinous neoplasms (AMNs). In 50% of female patients, AMNs (particularly LAMNs) have a tendency to metastasize to organs in the genital tract, where the neoplasm can mimic the features of primary ovarian mucinous cancer (POMC). The present case report reviewed the difficulties in differentiating between these two types of tumors. In the present case report, a 61-year-old female patient was admitted to the Second Department of Gynecological Surgery and Gynecological Oncology, University Clinical Hospital no. 4 at Lublin Medical University (Lublin, Poland) with the diagnosis of a right ovarian mass. After performing ultrasound and computed tomography (CT) scans and laboratory analysis, the patient underwent total abdominal hysterectomy, bilateral salpingo-oophorectomy, omentectomy, appendectomy and resection of the Douglas peritoneum. Notably, the postoperative pathological assessment revealed LAMN with metastases to the right ovary and omentum. Immunohistochemically, cytokeratin 20 and caudal type homeobox 2 both stained positively, whereas paired box gene 8 stained negatively. After surgery, the patient received the recommended hyperthermic intraperitoneal chemotherapy at the Department of Surgical Oncology at Lublin Medical University. After 1 year, a CT scan was performed, which indicated no evidence of recurrent disease. In conclusion, observations from the present case report suggest that gynecologists should be conscious of the possibility of malignancies of gastrointestinal origin in cases of ovarian tumors instead of making direct assumptions of POMC. If the mucinous mass involves the base of the appendix or if there is a suspicion of positive margins, then cytoreductive surgery and right-sided hemicolectomy must be performed. In addition, identifying the origin of mucinous tumors in the right ovary and/or the appendix requires the histopathological examination of a panel of markers using immunohistochemistry.

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.

An Incidental Finding of Low-Grade Appendiceal Mucinous Neoplasm in a Case of Borderline Brenner Tumor of the Ovary

The concurrent presentation of a low-grade appendiceal mucinous neoplasm (LAMN) and a borderline Brenner tumor (BT) of the ovary are exceedingly rare. Brenner tumors stand out as a particularly uncommon form, making up only around 5% of all benign epithelial tumors of the ovary. Among the ovarian Brenner, the borderline subtype is even rarer. Appendiceal neoplasm (LAMN) and right ovarian BT cannot be distinguished due to their anatomical position. LAMN is often an incidental finding and at later stages when left undiagnosed may lead to pseudomyxoma peritonei (PMP). This case describes a postmenopausal woman in her 50s experiencing abdominal pain and bloating for a week. Elevated carcinoembryonic antigen (CEA) levels and imaging suggested a potential right ovarian tumor. Interestingly, it revealed a unique combination of borderline Brenner tumor of the right ovary and low-grade appendiceal mucinous neoplasm.

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.

Treatment Variation and Long-Term Outcomes of Low-Grade Appendiceal Neoplasms

BACKGROUND

Heterogenous nomenclature describing appendiceal neoplasms has added to uncertainty around their appropriate treatment. Although a recent consensus has established the term low-grade appendiceal neoplasm (LAMN), we hypothesize that significant variation remains in the treatment of LAMNs.

METHODS

We retrospectively reviewed our prospectively maintained appendiceal registry, identifying patients with LAMNs from 2009 to 2019. We assessed variability in treatment, including whether patients underwent colectomy, spread of disease at presentation, and long-term outcomes.

RESULTS

Of 136 patients with LAMNs, 88 (35%) presented with localized disease and 48 (35%) with disseminated peritoneal disease. Median follow-up was 2.9 years (IQR 1.9-4.4), and 120 (88%) patients underwent pre-referral surgery. Among 26 pre-referral colectomy patients, 23 (88%) were performed for perceived oncologic need/nodal evaluation; no nodal metastases were identified. In patients with resected LAMNs without radiographic evidence of disseminated disease, 41 (47%) underwent second look diagnostic laparoscopy (DL) to evaluate for occult metastases. No peritoneal metastases were identified. Patients with disseminated disease were treated with cytoreductive surgery/heated intraperitoneal chemotherapy (CRS/HIPEC). For patients undergoing CRS/HIPEC, 5-year recurrence-free survival was 94% (95% CI 81-98%). For patients with localized disease, 5-year RFS was 98% (95% CI 85-99%).

CONCLUSIONS

Significant variation exists in treatment patterns for LAMNs, particularly prior to referral to a high-volume center. Patients frequently underwent colectomy without apparent oncologic benefit. In the current era of high-quality cross sectional imaging, routine use of DL has low yield and is not recommended. Recurrence in this population is rare, and low-intensity surveillance can be offered. Overall prognosis is excellent, even with peritoneal disease.

[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.

Appendiceal neoplasms: Suspected findings and reports of 14 cases

Background

Neoplastic lesions of the vermiform appendix are still considered to be rare, some studies suggest that appendix cancer may be on the rise, with an estimated incidence of 0.08-0.1% of all appendiceal specimens. The lifetime incidence of malignant appendiceal tumors ranges from 0.2 to 0.5%.

Patients and Methods

Our study is applied at the Department of General Surgery at tertiary training and research hospital; 14 patients who had appendectomy or right hemicolectomy between December 2015 and April 2020 were evaluated.

Results

The mean age of the patients was 52.3 ± 15.1 (range, 26-79) years. Gender of the patients were: five (35.7%) men and nine (64.3%) women. The clinical diagnosis was appendicitis without suspected findings in 11 (78.6%), appendicitis with suspected findings (appendiceal mass, etc.) in three (21.4%) of the patients, and there is no patient with asymptomatic or other rare findings. Surgeries applied for the patients were: nine (64.3%) underwent open appendectomy, four (28.6%) underwent laparoscopic appendectomy, and one (7.1%) underwent open right hemicolectomy. Histopathologic results were as follows: five (35.7%) neuroendocrine neoplasm, eight (57.1%), noninvasive mucinous neoplasm, and one (7.1%) adenocarcinoma.

Conclusion

While diagnosis and management of appendiceal pathology, surgeons should be familiar with suspected findings of appendiceal tumors and discuss them with patients to the possibility of histopathologic results.

Retrospective Review of Outcomes in Non-Invasive Mucinous Appendiceal Neoplasms with and without Peritoneal Spread: A Cohort Study

Patients treated surgically for local non-invasive mucinous appendiceal neoplasm (NI-MAN) may recur with the development of peritoneal dissemination (PD). The risk of recurrence and predictive factors are not well studied. Patients with NI-MAN, with or without peritoneal dissemination at presentation, were included. Patients with limited disease underwent surgical resection only. Patients with peritoneal dissemination underwent cytoreductive surgery (CRS) with or without hyperthermic intraperitoneal chemotherapy (HIPEC). Patients without PD (nPD) were compared to those who presented with PD. Thirty-nine patients were included, 25 in nPD and 14 in PD. LAMN was diagnosed in 96% and 93% of patients in nPD and PD, respectively. Acellular mucin on the peritoneal surface was seen in 16% of nPD patients vs. 50% of PD patients (p = 0.019). Two (8%) patients in the nPD group who had LAMN without wall rupture recurred, at 57 and 68 months, with a PCI of 9 and 22. The recurrence rate in the PD group was 36%. All recurred patients underwent CRS+HIPEC. A peritoneal recurrence is possible in NI-MANs confined to the appendix even with an intact wall at initial diagnosis. The peritoneal disease may occur with significant delay, which is longer than a conventional follow-up.

Appendiceal Mucinous Tumor Presenting as Recurrent Bowel Obstruction

Appendiceal mucinous tumors are rare, with variable malignant potential, and they are usually found incidentally. Clinical symptoms are nonspecific. Rarely, appendiceal mucinous neoplasm causes bowel obstruction and makes diagnosis more difficult. We present a case of an 84-year-old female who came to our emergency department having had abdominal fullness and constipation for 5 days. Ileus, due to an affected adhesion band, was diagnosed initially, and symptoms improved gradually under conservative treatment. However, 3 months later she presented to the emergency department again with abdominal pain and distension; small bowel obstruction due to adhesion was again diagnosed. Recurrent bowel obstruction prompted emergent surgery. Operative findings showed a whitish appendiceal tumor adhering to and directly invading the adjacent ileum, with a segment of herniated small bowel wedged in between, causing the obstruction. Upon reviewing the initial computed tomography scan, the dilated tubular structure of appendiceal tumor was misrecognized as small bowel loop; there was no surrounding inflammatory sign, leading to diagnosis difficulty. Instead of a common cause of bowel obstruction, such as adhesion band, this case revealed bowel obstruction can be caused by the direct invasion of an appendiceal tumor. Awareness of this condition with careful image evaluation of small bowel obstruction is essential for diagnosis.

Clinicopathologic parameters and outcomes of mucinous neoplasms confined to the appendix: a benign entity with excellent prognosis

Appendiceal mucinous neoplasms (AMNs), characterized by expansile or "pushing" growth of neoplastic epithelium through the appendix wall, are sometimes accompanied by peritoneal involvement, the extent and grade of which largely determine clinical presentation and long-term outcomes. However, the prognosis of tumors entirely confined to the appendix is still debated and confusion remains regarding their biologic behavior and, consequently, their clinical management and even diagnostic nomenclature. We evaluated AMNs limited to the appendix from 337 patients (median age: 58 years, interquartile range (IQR): 47-67), 194 (57.6%) of whom were women and 143 (42.4%) men. The most common clinical indication for surgery was mass or mucocele, in 163 (48.4%) cases. Most cases (N = 322, 95.5%) comprised low-grade epithelium, but there were also 15 (4.5%) cases with high-grade dysplasia. Lymph nodes had been harvested in 102 (30.3%) cases with a median 6.5 lymph nodes (IQR: 2-14) per specimen for a total of 910 lymph nodes examined, all of which were negative for metastatic disease. Histologic slide review in 279 cases revealed 77 (27.6%) tumors extending to the mucosa, 101 (36.2%) to submucosa, 33 (11.8%) to muscularis propria, and 68 (24.4%) to subserosal tissues. In multivariate analysis, deeper tumor extension was associated with older age (p = 0.032; odds ratio (OR): 1.02, 95% confidence intervals (CI): 1.00-1.03), indication of mass/mucocele (p < 0.001; OR: 2.09, CI: 1.41-3.11), and wider appendiceal diameter, grossly (p < 0.001; OR: 1.61, CI: 1.28-2.02). Importantly, among 194 cases with at least 6 months of follow-up (median: 56.1 months, IQR: 24.4-98.5), including 9 high-grade, there was no disease recurrence/progression, peritoneal involvement (pseudomyxoma peritonei), or disease-specific mortality. These data reinforce the conclusion that AMNs confined to the appendix are characterized by benign biologic behavior and excellent clinical prognosis and accordingly suggest that revisions to their nomenclature and staging would be appropriate, including reverting to the diagnostic term mucinous adenoma in order to accurately describe a subset of them.

Survival and prognostic factors for postoperative primary appendiceal cancer: a retrospective cohort study based on the Surveillance, Epidemiology, and End Results database

BACKGROUND

The factors affecting the postoperative survival of patients with primary appendiceal cancer (PAC) have yet to be fully explored. And there are no clear guidelines for adjuvant treatment after appendectomy. Whether chemotherapy can prolong patient survival after appendectomy, is critical in guiding postoperative medications. The majority of studies on appendiceal cancer are single case reports, and they focused on the incidence of appendiceal cancer. The present study aimed to investigate the survival characteristics of patients with primary appendiceal cancer after surgery using the Surveillance, Epidemiology, and End Results (SEER) database.

METHODS

The data of 2,891 cases of primary appendiceal cancer between 2004 to 2015 were obtained from the SEER database and subjected to survival analysis using the Kaplan-Meier method and Cox proportional-hazards model. The annual percentage change (APC) was calculated using the weighted least squares method.

RESULTS

The overall age-adjusted incidence rate per 100,000 population steadily increased from 0.58 in 2004 to 1.63 in 2015. For patients who received chemotherapy, the median overall survival (OS) was 65 months and the 5-year OS rate was 51.9%, and for patients who did not receive chemotherapy or whose chemotherapy status was unknown, the median OS was not reached and the 5-year OS rate was 78.9%. Age [35< age <69: hazard radio (HR) =2.147; 95% confidence interval (CI): 1.442-3.197, P<0.001; age >69: HR =5.259; 95% CI: 3.485-7.937, P<0.001], race (White race: HR =0.728; 95% CI: 0.590-0.899, P=0.003), histologic type (mucinous neoplasm: HR =0.690; 95% CI: 0.580-0.821, P<0.001; malignant carcinoid: HR =0.657; 95% CI: 0.536-0.806, P<0.001), grade (II: HR =1.794; 95% CI: 1.471-2.187, P<0.001; III: HR =2.905; 95% CI: 2.318-3.640, P<0.001; IV: HR =3.128; 95% CI: 2.159-4.533, P<0.001), and stage (localized: HR =0.236; 95% CI: 0.194-0.287, P<0.001; regional: HR =0.425; 95% CI: 0.362-0.499, P<0.001) were identified as independent predictors of survival. And after adjusting for known factors (age, sex, race, tumor size, marital status, histologic type, grade, stage), chemotherapy (HR =1.220; 95% CI: 1.050-1.417, P=0.009) was revealed to be an independent indicator of poor prognosis.

CONCLUSIONS

There was an increasing trend in the incidence of appendiceal cancer in the United States between 2004 and 2015. Chemotherapy was revealed to be an independent indicator of poor prognosis, which provide valuable insight into the therapy of primary appendiceal cancer. Large clinical trials of chemotherapy and targeted therapy for appendiceal cancer are urgently needed.

Laparoscopic Right Hemicolectomy of a Low-Grade Appendiceal Mucinous Neoplasm Causing an Ileocolic Intussusception: A Case Report

Introduction

Intussusception, although common in the pediatric population, rarely occurs in adults. Furthermore, patients often show nonspecific symptoms. Most adult patients with intussusception have a surgical lead point, a well-defined pathological abnormality, often accurately diagnosed after surgery. A low-grade appendiceal mucinous neoplasm (LAMN), often misdiagnosed as acute appendicitis, is rarely associated with the development of intussusception. Here we report a case of LAMN-related ileocolic intussusception that was histologically diagnosed after laparoscopic right hemicolectomy.

Case presentation

A 58-year-old woman visited our emergency department because of intermittent episodes of epigastric pain with periumbilical tenderness. These symptoms persisted intermittently for 2 weeks. The pain was moderate in severity, colicky in nature, and sometimes shifted to the lower abdominal region. Abdominal computed tomography indicated intussusception with ileocecal and mesenteric telescoping into the transverse colon. Complete colonoscopy with reduction of intussusception was performed, revealing a ball-like mass protruding and occupying the entire cecum lumen. Laparoscopic right hemicolectomy was then performed. Macroscopically, a dilated appendix was revealed with mucin content, along with hyalinization and fibrosis of the appendiceal wall. Microscopically, a tumor exhibiting villous and flat proliferation of mucinous epithelial cells with low-grade nuclear atypia was seen. However, there was no infiltration growth of the tumor cells, thereby demonstrating LAMN. Postoperative recovery was uneventful, and the patient was discharged on the 8th postoperative day without surgical complications.

Conclusion

The differential diagnoses of chronic and colicky abdominal pain should be expanded to include intussusceptions as they can be severe, although cases in adults are rare.

Recurrence of initially localized appendiceal mucinous neoplasms after radical resection: survey analysis and literature review

BACKGROUND

Appendiceal mucinous neoplasm (AMN) is a rare tumor that may be successfully treated by appendectomy. However, some patients develop recurrence as pseudomyxoma peritonei. The present study investigated the recurrence rate after radial resection for AMN.

METHODS

A survey on AMN was sent to 171 institutions, and 286 cases were analyzed. The risk of recurrence was assessed according to clinical parameters. Recurrence rates were compared with data from the literature.

RESULTS

There were 250 cases in the low-grade group and 36 in the high-grade group, with perforation being detected in 50 cases. After a median follow-up period of 30 months, recurrence was detected in 17 cases, including 12 with high-grade histology and 10 with perforation. Two patients with low-grade histology and no perforation developed recurrence. Independent prognostic factors for recurrence were high-grade histology (p = 0.0001, RR = 8.56) and perforation (p = 0.0168, RR = 3.45). Four groups were classified by histology and perforation: group A: high-grade, perforation ( +), group B: high-grade, perforation (-), group C: low-grade, perforation ( +), group D: low-grade, perforation (-). Five-year recurrence rates in groups A, B, C, and D were 46.7, 25.9, 13.3, and 1.5%, respectively. All cases of recurrence were detected within 3 years, except for two in group B.

CONCLUSIONS

Recurrence in cases with low-grade histology and no perforation was rare; however, a postoperative survey for at least 3 years is required. In contrast, cases with high-grade histology or perforation need to be monitored using a similar approach to colon cancer. Prophylactic CRS + HIPEC may be considered.

Necessity of posttreatment surveillance for low-grade appendiceal mucinous neoplasms

BACKGROUND AND OBJECTIVES

Low-grade appendiceal mucinous neoplasms (LAMNs) are generally treated by surgical resection, but posttreatment surveillance protocols are not well-established. The objectives of this study were to characterize posttreatment surveillance and determine the risk of recurrence following surgical resection of LAMN.

METHODS

Patients who underwent surgical resection of localized LAMNs in an 11-hospital regional healthcare system from 2000 to 2019 were identified. Posttreatment surveillance regimens were characterized, and rates of disease recurrence were evaluated.

RESULTS

A total of 114 patients with LAMNs were identified. T-category was pTis for 92 patients (80.7%), pT3 for 7 (6.1%), pT4a for 14 (12.3%), and pT4b for 1 (0.9%). Two patients (1.8%) had a positive resection margin. Posttreatment surveillance was performed for 39 (34.2%) patients and consisted of office visits for 32 (82%) patients, computerized tomography imaging for 30 (77%), magnetic resonance imaging for 5 (13%), colonoscopy for 15 (38%), and serum tumor marker measurement for 12 (31%). After a mean follow-up duration of 4.7 years, no patients experienced tumor recurrence.

CONCLUSIONS

Posttreatment surveillance is common among patients with LAMNs. However, no patients experienced tumor recurrence, regardless of T-category or margin status, suggesting that routine surveillance following surgical resection of LAMN may be unnecessary.

Epidemiology, histopathology, clinical outcomes and survival of 50 cases of appendiceal mucinous neoplasms: Retrospective cross-sectional single academic tertiary care hospital experience

Background

Appendicular neoplasms are rare, most commonly as carcinoids followed by appendicular mucinous neoplasms (AMN). To date, there remains controversy regarding the best treatment of AMN and factors affecting its prognosis.

Method

Retrospective chart review of patients operated for appendicular pathology (January 2011–December 2018, follow up to December 2020) at our institution. For all AMN patients, data included pre-operative clinical presentation, and operative/post-operative findings.

Results

12454 patients underwent appendectomy, of whom 50 (0.4%) had AMN histopathologically (mean age = 47.2). Most patients had laparoscopic appendectomy as primary surgery. Low grade AMN was the most common subtype (n = 41, 82%), and pseudomyxoma peritonei (PMP) was found in 8 (16%) patients. Based on histopathology and margin involvement, the 50 patients were categorized into 3 prognostic categories of recurrence risk (no risk, 24 patients; low risk, 8; high recurrence risk, 18 patients). Disease-free survival (DFS) was lowest for high recurrence risk group (P < 0.001). Eleven (22%) patients had AMN involving resection margin, of whom 3 had no completion surgery and had no recurrence. Higher tumor markers were associated with lower DFS, however it was not statistically significant.

Conclusion

AMNs are rare but serious due to the risk of PMP. Laparoscopic approach for AMN may be feasible. Prognostic categories were significantly inversely correlated with recurrence risk; hence useful in predicting prognosis. Contrary to previous proposals, AMNs with acellular mucin at margin or local acellular mucin spillage may not require secondary surgery, especially if the patient is in low recurrence risk group. Tumor markers may predict risk of recurrence.

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Laparoscopic approach may be feasible for appendiceal mucinous neoplasms (AMN).

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AMN can be categorized into 3 risk recurrence groups (No risk, low, and high).

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AMN with acellular mucin at the margin may not require secondary surgery.

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Higher tumor markers may indicate high risk of AMN recurrence.

A Multi-institutional Study of Peritoneal Recurrence Following Resection of Low-grade Appendiceal Mucinous Neoplasms

BACKGROUND

Peritoneal dissemination of low-grade appendiceal mucinous neoplasms (LAMNs), sometimes referred to as pseudomyxoma peritonei, can result in significant morbidity and mortality. Little is known about the natural history of localized (non-disseminated) LAMNs.

OBJECTIVE

The goal of this study was to evaluate the risk of peritoneal recurrence in patients with localized LAMNs.

METHODS

We performed a multi-institutional retrospective review of patients with pathologically confirmed localized LAMNs. Baseline characteristics, pathology, and follow-up data were collected. The primary endpoint was the rate of peritoneal recurrence.

RESULTS

We identified 217 patients with localized LAMNs. Median age was 59 years (11-95) and 131 (60%) patients were female. Surgical management included appendectomy for 124 (57.1%) patients, appendectomy with partial cecectomy for 26 (12.0%) patients, and colectomy for 67 (30.9%) patients. Pathology revealed perforation in 46 patients (37.7% of 122 patients with perforation status mentioned in the report), extra-appendiceal acellular mucin (EAM) in 49 (22.6%) patients, and extra-appendiceal neoplastic cells (EAC) in 13 (6.0%) patients. Median follow-up was 51.1 months (0-271). Seven (3.2%) patients developed a peritoneal recurrence, with a median time to recurrence of 14.4 months (2.5-47.0). Seven (15.2%) patients with histologic evidence of perforation had recurrence, versus no patients (0%) without perforation (p < 0.001); five (10.2%) patients with EAM versus two (1.2%) patients without EAM (p = 0.007), and one (7.7%) patient with EAC versus six (2.9%) patients without EAC (p = 0.355) had recurrence.

CONCLUSIONS

This multi-institutional study represents the largest reported series of patients with localized LAMNs. In the absence of perforation or extra-appendiceal mucin or cells, recurrence was extremely rare; however, patients with any of these pathologic findings require careful follow-up.

Predictors of Progression of Appendiceal Mucinous Neoplasm to Pseudomyxoma Peritonei

Appendiceal mucinous neoplasm (AMN) can present with a spectrum of disease. Predicting factors in development of pseudomyxoma peritonei (PMP) from AMN could aid in management and treatment. The aim of this study was to determine factors predictive of PMP from AMN. This was a retrospective multicenter study of all patients diagnosed with AMN from 2006-2017. Diagnosis of PMP was compared by (1) patient demographics, (2) tumor characteristics, and (3) surgery. Secondary end points were disease-specific survival (DSS) and overall survival (OS).One-hundred thirty-eight patients with AMN were identified. Thirty-six patients (26.1%) had a ruptured appendix at presentation, and 12 patients (8.7%) were diagnosed with PMP during the study period. Eight patients presented with PMP at the time of surgery. No demographic factors were predictive of PMP. Operative approach and extent of initial resection did not correlate with PMP. Tumor rupture at presentation was the only factor associated with PMP, though only 14% of patients who presented with simple rupture eventually progressed to PMP.OS was not different between those who were diagnosed with PMP and those who were not. DSS was significantly lower for the group diagnosed with PMP (P = .007). Tumor rupture at presentation did not influence OS or DSS. The only factor found to be significantly associated with PMP was tumor rupture at presentation. Diagnosis of PMP did not affect OS but did lead to decreased DSS.In conclusion, though a majority of patients who presented with rupture did not go on to develop PMP, tumor rupture at presentation was the only factor significantly associated with PMP. Diagnosis of PMP did not affect OS at 5 years. In patients with AMN who present with a ruptured appendix on final pathology, we recommended continued surveillance, though overall risk of PMP is relatively low.

Updates in Appendix Pathology: The Precarious Cutting Edge

Mucinous appendiceal tumors include low-grade appendiceal mucinous neoplasm, high-grade appendiceal mucinous neoplasm, and mucinous adenocarcinoma. Nonmucinous adenocarcinomas are less frequent. Recent consensus guidelines and the latest edition of the World Health Organization classification will allow consistent use of agreed nomenclature. Accurate diagnosis is important not only for patient management but also to allow comparison of results between centers and tumor registries. Serrated polyps are the most common benign polyp in the appendix. They need to be distinguished from low-grade appendiceal mucinous neoplasm, which can also mimic other benign conditions. Goblet cell adenocarcinomas are a distinctive type of appendiceal neoplasm.

Surgical management of appendiceal mucinous neoplasm: Is appendectomy sufficient?

BACKGROUND AND OBJECTIVES

Due to the rarity of appendiceal mucinous neoplasms (AMNs), there are few established treatment guidelines. The clinical course varies from incidental detection to progressive spread with pseudomyxoma peritonei (PMP). This study investigated the extent of resection on the prognosis and outcomes of AMNs.

METHODS

This multicenter retrospective study evaluated patients with AMN who underwent surgery between 4/2006 to 9/2017. Primary endpoints included overall survival (OS) and disease-specific survival (DSS). Secondary endpoints included PMP incidence and treatment with cytoreductive surgery (CRS).

RESULTS

Of the 138 patients with AMN, 70 patients (54%) underwent appendectomy, 26 (19%) cecectomy, and 37 (27%) right hemicolectomy. The median age was 59.7 years and 57 patients (41%) were male. Males were less likely to undergo cecectomy (P = .03). Rupture rates, tumor characteristics, and incidence of PMP were similar across surgery groups. Median follow-up was 61.3 months. Five-year OS and DSS for the total cohort were 94.9% and 98.6%, respectively, and remained similar across all surgery groups. CRS patients were more likely to undergo right hemicolectomy with no difference in survival by surgery type (P = .03).

CONCLUSIONS

Patients with AMN have a good overall prognosis and there may be minimal benefit to performing extended surgical resection in these patients.

Low-Grade Appendiceal Mucinous Neoplasm in an Adolescent Patient With Untreated Crohn's Disease

Appendiceal mucinous neoplasms are rarely diagnosed in pediatric patients. We present a 16-year-old adolescent boy with severe Crohn's disease who was not on maintenance medication for his underlying diagnosis. He was referred for nutritional optimization and small bowel obstruction. An emergent laparoscopic ileocecectomy with primary ileocolonic anastomosis was carried out secondary to acute peritonitis. Small bowel pathologic findings were consistent with Crohn's disease with low-grade appendiceal mucinous neoplasm (LAMN) of the appendix.

Analysis of Clinical Characteristics of Low-Grade Appendiceal Mucinous Neoplasm (LAMN): A Retrospective Cohort Study of 51 LAMN Patients

INTRODUCTION

Low-grade appendiceal mucinous neoplasm (LAMN) is a rare disorder. There is no consensus on the prognosis and management of LAMN.

MATERIALS AND METHODS

We reviewed 51 consecutive patients with LAMN from 2013 to 2018. We divided our patients into two groups. The first is patients with an intact appendix. The second group comprises patients with the potential to develop a malignant condition. Comparisons of serum tumor markers between two groups were performed. Survival curves were estimated. Univariate and multivariate Cox proportional hazards were computed for 46 patients with median follow-up of 2.7 years.

RESULTS

Comparison of patients in two groups revealed significant differences in the mean level and abnormal ratio of CA125 (p < 0.001, p < 0.001), CA19-9 (p = 0.04, p = 0.04), and CEA (p = 0.001, p = 0.02). Eight patients had relapsed by the last follow-up in the second group. Patients with normal CEA had significantly longer disease-free survival (DFS) time than those with abnormal CEA (p = 0.04). CA19-9 exhibited a significant association with DFS (HR = 5.72, p = 0.02) in the Univariate Cox proportional hazards.

DISCUSSION

The prognosis of LAMN is related to serum tumor markers, the surgical procedure and the pathology.

Incidence and survival trends for appendiceal mucinous adenocarcinoma: an analysis of 3237 patients in the Surveillance, Epidemiology, and End Results database

Aim: To characterize the epidemiology of appendiceal mucinous adenocarcinoma. Methods: Prognostic factors were evaluated with univariate and multivariate analyses. The results were used to generate a nomogram. Results: The incidence of appendiceal mucinous adenocarcinoma showed a significant upward trend. Multivariate Cox analysis identified 11 independent prognostic factors. The nomogram was based on independent risk factors that were significant in multivariate Cox analysis, and the concordance-index for overall survival and cancer-specific survival were 0.76 (95% CI: 0.71-0.79) and 0.74 (95% CI: 0.70-0.79), respectively. Conclusion: Advanced age, single relationship status, male sex, black race, the presence of distant and regional lymph node metastases, poor differentiation or lack of differentiation, advanced SEER extent of disease, cancer-directed surgery and chemotherapy were independently associated with prognosis.