Correction to: Clinical Surveillance After Macroscopically Complete Surgery for Low-Grade Appendiceal Mucinous Neoplasms (LAMN) with or Without Limited Peritoneal Spread: Long-Term Results in a Prospective Series

Mucinous appendiceal neoplasms: Report of a case and brief literature review

INTRODUCTION

Appendiceal tumors are rare neoplasms detected in about 2 % of appendicectomies. The clinical presentation is often unspecific, varying from unspecific abdominal pain or presenting as an acute appendicitis or being asymptomatic.

CASE PRESENTATION

We present a case of a patient presenting as an acute appendicitis with a mucocele, and then classified as HAMN. The patient was treated with initial laparoscopic approach and then conversion in laparotomy with appendectomy. Histology demonstrated a high grade appendiceal mucinous neoplasm limited to submucosa (pT3), with concomitant acute phlegmonous appendicitis. The patient was subsequently sent to a referral center where a right hemicolectomy with HIPEC was performed.

DISCUSSION

HAMN is a rare entity, only recently classified as a new kind of appendiceal mucinous neoplasm. Due to the supposed higher aggressivity, HAMN must be treated as an appendiceal adenocarcinoma. The treatment of this rare entity is not yet well standardized, because of the rarity of this disease.

CONCLUSION

HAMN is a very rare tumor. In the emergency setting, it is mandatory to avoid rupture of the appendix, to minimize the risk of developing pseudomyxoma peritonei. Pathology is essential for further decisions in these patients and plays a very important role in treatment and prognosis.

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.

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

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

Diagnostic and Therapeutic Algorithm for Appendiceal Tumors and Pseudomyxoma Peritonei: A Consensus of the Peritoneal Malignancies Oncoteam of the Italian Society of Surgical Oncology (SICO)

Aim: Pseudomyxoma peritonei (PMP) is an uncommon pathology, and its rarity causes a lack of scientific evidence, precluding the design of a prospective trial. A diagnostic and therapeutic algorithm (DTA) is necessary in order to standardize the disease treatment while balancing optimal patient management and the correct use of resources. The Consensus of the Italian Society of Surgical Oncology (SICO) Oncoteam aims at defining a diagnostic and therapeutic pathway for PMP and appendiceal primary tumors applicable in Italian healthcare. Method: The consensus panel included 10 delegated representatives of oncological referral centers for Peritoneal Surface Malignancies (PSM) affiliated to the SICO PSM Oncoteam. A list of statements regarding the DTA of patients with PMP was prepared according to recommendations based on the review of the literature and expert opinion. Results: A consensus was obtained on 33 of the 34 statements linked to the DTA; two flowcharts regarding the management of primary appendiceal cancer and peritoneal disease were approved. Conclusion: Currently, consensus has been reached on pathological classification, preoperative evaluation, cytoreductive surgery technical detail, and systemic treatment; some controversies still exist regarding the exclusion criteria for HIPEC treatment. A shared Italian model of DTA is an essential tool to ensure the appropriateness and equity of treatment for these patients.

Laparoscopic cytoreductive surgery and HIPEC in LAMN with small volume of peritoneal disease: a valuable option of treatment for good patient-related experience measures (PREMs)

BACKGROUND

Cytoreductive surgery (CRS) and hyperthermic intraperitoneal chemotherapy (HIPEC) is the best effective treatment for pseudomyxoma peritonei (PMP). In the last years, the advances in histopathology have stratified PMP lesions in different degrees of aggressivity suggesting the possibility of a tailored treatment. In a subset of patients with small volume peritoneal disease, laparoscopic CRS and HIPEC is feasible. The aim of this study is to analyze the results of laparoscopic CRS + HIPEC in a monocentric series of patients under patient-related experience measures (PREMs).

METHODS

All consecutive patients who underwent laparoscopic CRS-HIPEC with curative intent at Cancer Institute of Montpellier were retrieved from a prospectively maintained database and analyzed. Selection criteria for laparoscopic approach were low-grade PMP with pathological confirmation prior to CRS-HIPEC, age < 75 years, no extra-peritoneal disease, peritoneal cancer index (PCI) < 10, and a limited history of abdominal surgery. A PREMS interview was conducted before analysis with all the included patients. Outcomes of interest included postoperative morbidity, medium-term survival, and PREMs.

RESULTS

Fourteen patients were operated on for low-grade PMP with a laparoscopic approach at our institution. Conversions to laparotomy were necessary in three patients, and postoperative complications were observed in three patients (Clavien 3b in one patient). In-hospital postoperative median stay was 9.5 days. No death or recurrence was observed during the study period.

CONCLUSIONS

Laparoscopic CRS-HIPEC for LAMN in presence of small peritoneal disease is feasible in terms of postoperative morbidity and mortality. According to our PREMs questionnaire, patients' expectations were satisfied.

Novel Perspectives in Pseudomyxoma Peritonei Treatment

Simple Summary

Pseudomyxoma Peritonei (PMP) represents a rare entity which greatly benefits from Cytoreductive Surgery (CRS) associated with Hyperthermic Intraperitoneal Chemotherapy (HIPEC). In fact, CRS-HIPEC represents the treatment with potential chances of cure and long-term disease control of patients affected by PMP. This therapeutic strategy should be performed in referral centers, where a consolidated know-how of this locoregional treatment and a multidisciplinary approach are available. CRS-HIPEC provides excellent results for PMP patients in terms of postoperative outcome, overall and disease-free survival, and quality of life. However, in patients with an extensive or recurrent disease, few therapeutic opportunities are available. This review is focused on the most recent clinical evidence and provides a better understanding of the molecular prognostic factors and potential therapeutic targets in this rare malignancy.

Abstract

Pseudomyxoma Peritonei (PMP) is an anatomo-clinical condition characterized by the implantation of neoplastic cells on peritoneal surfaces with the production of a large amount of mucin. The rarity of the disease precludes the evaluation of treatment strategies within randomized controlled trials. Cytoreductive Surgery (CRS) combined with Hyperthermic Intraperitoneal Chemotherapy (HIPEC) has proven to be the only therapeutic option with potential chances of cure and long-term disease control. The present review discusses the epidemiology, pathogenesis, clinical presentation and treatment of PMP, focusing on the molecular factors involved in tumor progression and mucin production that could be used, in the upcoming future, to improve patient selection for surgery and to expand the therapeutic armamentarium.

Surveillance Colonoscopy Revealing Asymptomatic Low-Grade Appendiceal Mucinous Neoplasm

Appendicular mucinous neoplasms are a collection of rare tumors with diverse clinical presentations and pathologic potential, which can cause diagnostic and therapeutic challenges. Traditionally, they are diagnosed by radiologic imaging or identified intraoperatively; however, rarely, they may be diagnosed during an endoscopic procedure. In this unusual case, we present the case of a 62-year-old Caucasian male undergoing routine surveillance colonoscopy due to a history of colonic neoplasia. During the colonoscopy, a submucosal, non-bleeding 1cm mass of benign appearance was found in the appendix. Further workup determined the mass was likely a mucocele, and surgical consultation was recommended. The patient denied any symptoms suggestive of a mucinous neoplasm prior to and during evaluation. A laparoscopic appendectomy was subsequently performed, and the histopathology report confirmed the diagnosis of a low-grade appendiceal mucinous neoplasm. The patient recovered without complications and continued to deny any symptoms during his postoperative course and follow-up care. Given their rare incidence and unpredictable nature, appendiceal mucinous neoplasms remain difficult to identify. Discovering a low-grade mucinous neoplasm in an asymptomatic patient via colonoscopy illustrates the spectrum of unique presentations and modalities for diagnosis.

Procedure of choice in a patient initially operated for a suspected epithelial appendiceal neoplasm

In patients operated for a suspected appendiceal neoplasm, radical appendectomy is the procedure of choice because it provides definitive treatment in most of appendiceal neoplasms, except from mucinous or colonic-type adenocarcinoma and NET>2 cm.

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.

Updated staging and patient outcomes in low-grade appendiceal mucinous neoplasms

Low-grade appendiceal mucinous neoplasms (LAMNs) exhibit drastically different clinical course and prognosis depending on tumor stage, particularly as it relates to the extent and cellularity of peritoneal involvement. In this context, recent changes in staging guidelines have sought to clarify criteria for pT and pM categories. This study's aim was to identify clinicopathological features associated with patient outcomes, especially as they pertain to updated stage groups. We reviewed LAMNs from 192 patients (mean age: 56.9 years, 119 (62.0%) women). The tumors consisted of 66 (34.4%) pTisM0, 16 (8.3%) pT3M0, 16 (8.3%) pT4aM0, 27 (14.1%) pTxM1a, and 67 (34.9%) pTxM1b cases. In multivariate analysis, only gross perforation was significantly associated with higher TNM group stage (p = 0.001; OR 3.3, 95% CI: 1.7-6.4). Of 165 (85.9%) patients with clinical follow-up, 51 (30.9%) had disease progression (over a mean 33.7 months, range: 4.7-121.7), whereas over significantly longer follow-up (mean 48.7 months, range: 3.1-143.9; p = 0.004), 114 (69.1%) patients did not. In multivariate analysis, higher TNM stage was significantly associated with disease progression (p = 0.029; OR 18.3, 95% CI: 1.4-246.0). In Kaplan-Meier analysis, none of 74 patients with disease limited to the appendix (pM0), 6 of 27 (22.2%) cases with peritoneal involvement by acellular mucin only (pM1a), and 45 of 64 (70.3%) tumors with intraperitoneal deposits containing neoplastic cells (pM1b) showed disease progression (p < 0.001). These differences in progression-free survival among TNM groups persisted when limiting the analysis to patients who had undergone successful cytoreductive surgery (p = 0.050). Finally, in four patients (all with pM1b disease) death was attributed to disease progression whereas there was no disease-specific mortality in the pM0 and pM1a groups (p = 0.020). These data support the designation of LAMNs with acellular peritoneal mucin as having an intermediate prognosis between cases limited to the appendix and those with intraperitoneal deposits containing neoplastic epithelium.

Immune response activation following hyperthermic intraperitoneal chemotherapy for peritoneal metastases: A pilot study

BACKGROUND

Hyperthermic intraperitoneal chemotherapy (HIPEC) for peritoneal metastases (PM) is considered to be feasible, safe and to improve survival.

AIM

To investigate whether an immune response is activated following HIPEC for PM.

METHODS

Six patients were enrolled in this study. Peripheral blood samples were obtained from each patient prior to (day 0) and post-procedure (day 30), and used to evaluate the number of CD3⁺ total, CD3⁺/CD4⁺ T-Helper, CD3⁺/CD8⁺ cytotoxic T, CD3⁺/CD56⁺ natural killer and CD19⁺ B lymphocyte numbers, and CD4⁺: CD8⁺ T lymphocyte ratios.

RESULTS

The total numbers of CD3⁺, CD3⁺/CD4⁺ T-Helper, CD3⁺/CD8⁺ cytotoxic T, CD3⁺/CD56⁺ natural killer and CD19⁺ B lymphocytes, and CD4⁺: CD8⁺ lymphocyte ratios were increased in all but one patient 30 d following the cytoreductive surgery-HIPEC procedure, and these increases were significant (P ≤ 0.05) for CD3⁺/CD4⁺ T Helper and CD3⁺/CD8⁺ cytotoxic T lymphocyte numbers.

CONCLUSION

This report provides the first evidence that HIPEC exhibits immunomodulating activity in PM patients, resulting in generalized activation of the adaptive immune response. Moreover, the majority of lymphocyte populations increased following HIPEC and continued to be elevated several weeks following the procedure, consistent with a potential authentic immunomodulating effect rather than a normal inflammatory response, to be fully characterised in future studies.

Local Protocol for Management of Low-Grade Appendiceal Mucinous Neoplasm (LAMN)

The management and surveillance of low-grade appendiceal mucinous neoplasm (LAMN) is a confusing topic in the colorectal MDM. This study was aiming to provide a local protocol for our trust for such cases. From prospectively maintained database, patients who underwent appendicectomy between 2011 and 2017 were identified. Those with histological confirmation of LAMN were included. Retrospective analysis of operative notes, investigations and follow-up, return to theatres or development of pseudomyxoma peritonei (PMP) was performed. Four thousand six hundred twenty-eight patients had appendicectomy; 36 were diagnosed with LAMN. Age range was 30-88 (20 females). Fifteen had their operation as emergency and 13 elective, either for abnormal-looking appendix on CT scan or as part of elective right hemicolectomy. In 8 patients, LAMNs were diagnosed incidentally during other surgery either intraoperatively or on histology. Two patients had mucus in the peritoneal cavity (not sampled). The remaining 34 had either contained mucocele or inflamed appendix. Regarding follow-up, 28 patients had CT scans only, and 2 had ultrasound scan (USS). Two had both CT and USS. Three had CT and MRI scans. One patient did not have radiological investigations. Eighteen patients had colonoscopies (50%). Three patients had no follow-up, while 33 had 5-year follow-up. Ten patients are still currently under follow-up. None of the 36 patients required further surgeries related to LAMN, and none has developed PMP to date of the study. We have developed a local protocol based on our findings and literature review for management and surveillance of LAMN in line with national centres.

Low grade appendiceal mucinous neoplasm mimicking an ovarian cyst: A case report

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Appendiceal mucocele defines as an intraluminal dilation of the appendix in response to mucin accumulation.

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This condition overall is very rare with a 0.2–0.3% incidence of all appendectomy specimens.

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It's more common in the females with a 4 to 1 ratio.

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Appropriate diagnosis and management of appendiceal mucocele prevent complications such as pseudomyxoma peritonei.

Introduction

Appendiceal mucocele (AM) is a very rare neoplasm with an incidence of 0.2–0.3% of all appendectomy specimens. AM usually defined as an intraluminal dilation of the appendix in response to mucin accumulation. The preoperative diagnosis is difficult and can be misdiagnosed to any of the other differential diagnosis especially in female patients. If it is suspected, imaging modalities and colonoscopy can be helpful as a guide for the right surgical approach.

Presentation of case

A 41-year-old lady who found to have an appendicular tumor discovered incidentally on magnetic resonance imaging (MRI) of the abdomen during a follow-up in the referral hospital for persistent right lower quadrant abdominal pain with enlarging right ovarian cyst for 2 years. MRI revealed a sizeable cyst measuring 7 × 4 × 3 cm in the right iliac fossa (RIF) region with high suspicion of an AM. The patient was managed with open right limited hemicolectomy. The patient was diagnosed as a well-differentiated low-grade AM neoplasm with stage 0 (pTis, pN0, M0) based on the 8th edition of the American Joint Committee on Cancer (AJCC) Staging System. The patient had an uneventful recovery and advised for regular follow-up of at least 5 years.

Discussion

AM is a very rare neoplasm. The imaging modalities that can be diagnostic methods are the abdominal ultrasonography (US), transvaginal US, abdominal computed tomography (CT) and abdominal MRI. Fine needle aspiration must be avoided as the risk of perforation is high that will lead to dissemination of the mucinous material causing a serious complication called pseudomyxoma peritonei. Laparotomy is superior on laparoscopy as the risk of perforation is lower in laparotomy.

Conclusion

The presentation of AM is usually not specific, because of its anatomic position. Physicians should consider it in the differential diagnosis of persistent enlarging ovarian cyst or adnexal mass.

Essentials for Pathological Evaluation of Peritoneal Surface Malignancies and Synoptic Reporting of Cytoreductive Surgery Specimens-A review and evidence-based guide

Peritoneal surface oncology has emerged as a subspecialty of surgical oncology, with the growing popularity of surgical treatment of peritoneal metastases comprising of cytoreductive surgery (CRS) and hyperthermic intraperitoneal chemotherapy (HIPEC). Pathological evaluation plays a key role in multidisciplinary management but there are still many areas where there are no guidelines or consensus on reporting. Some tumors presenting to a peritoneal surface oncology unit are rare and pathologists my not be familiar with diagnosing and classifying those. In this manuscript, we have reviewed the evidence regarding various aspects of histopathological evaluation of peritoneal tumors. It includes establishing a diagnosis, appropriate classification and staging of common and rare tumors and evaluation of pathological response to chemotherapy. In many instances, the information captured is of prognostic value alone with no direct therapeutic implications. But proper capturing of such information is vital for generating evidence that will guide future treatment trends and research. There are no guidelines/data set for reporting cytoreductive surgery specimens. Based on the authors' experience, a format for handling/grossing and synoptic reporting of these specimens is provided.

Low-grade Appendiceal Mucinous Neoplasm and Endometriosis: Incidental Coincident Pathologies at Cesarean Section

Incidental pathologic findings at the time of Cesarean section are exceedingly uncommon. Similarly, occult low-grade appendiceal mucinous neoplasms and other noninflammatory, non-neoplastic appendiceal pathologies are rare, although appendiceal neoplasia, most commonly well-differentiated neuroendocrine tumors, may be found during evaluation of acute appendicitis. Here we report the first case of incidental coincident low-grade appendiceal mucinous tumor and endometriosis involving the appendix at the time of Cesarean section. We highlight pitfalls in the histopathologic evaluation of these processes, particularly given the setting of decidualization of ectopic endometrial stroma, as well as the prognostic implications of low-grade appendiceal mucinous tumors to emphasize the importance of clinicopathologic correlation and careful intraoperative examination of the appendix and other visible structures during Cesarean section.

[Incidental finding of mucinous neoplasia of the appendix : Treatment strategies]

Tumors of the appendix are not a uniform group but differ significantly in terms of their origin/histology and metastatic behavior. Furthermore, tumors of the appendix are often diagnosed as incidental findings after appendectomy for acute appendicitis. A subgroup of these neoplasms are low-grade appendiceal mucinous neoplasms (LAMN). These are mucus-forming tumors of the appendiceal lumen, which can lead to rupture of the appendix and seeding into the abdominal cavity. Therefore LAMN are considered precursors of pseudomyxoma peritonei (PMP). It is essential to clearly differentiate the subgroups of LAMN as well as the resection status. According to this it is determined whether (radical) appendectomy is a sufficient therapy or further treatment, such as ileocecal resection with hyperthermic intraperitoneal chemotherapy (HIPEC) or cytoreductive surgery (CRS) is necessary. There is no standardized concept regarding the follow-up after resection of LAMN. Generally, it is recommended to perform a computed tomography (CT) scan of the abdomen and determination of tumor markers 6 months postoperatively and then once a year. A recommendation regarding the duration of follow-up is difficult as there are case reports in which PMP has occurred more than 15 years after removal of LAMN.