Review

Authors: Franziska Köhler, Niels Matthes, Mathias Rosenfeldt...

BACKGROUND

Neoplasms of the vermiform appendix are rare. They comprise a heterogeneous group of entities requiring differentkinds of treatment.

METHODS

This review is based on publications retrieved by a selective literature search in the PubMed, Embase, and Cochranedatabases.

RESULTS

0.5% of all tumors of the gastrointestinal tract arise in the appendix. Their treatment depends on their histopathologicalclassification and tumor stage. The mucosal epithelium gives rise to adenomas, sessile serrated lesions, adenocarcinomas,goblet-cell adenocarcinomas, and mucinous neoplasms. Neuroendocrine neoplasms originate in neuroectodermal tissue. Adenomasof the appendix can usually be definitively treated by appendectomy. Mucinous neoplasms, depending on their tumorstage, may require additional cytoreductive surgery (CRS) and hyperthermic intraperitoneal chemoperfusion (HIPEC). Adeno -carcinomas and goblet-cell adenocarcinomas can metastasize via the lymphatic vessels and the bloodstream and should thereforebe treated by oncological right hemicolectomy. Approximately 80% of neuroendocrine tumors are less than 1 cm in diameterwhen diagnosed and can therefore be adequately treated by appendectomy; right hemicolectomy is recommended if the patienthas risk factors for metastasis via the lymphatic vessels. Systemic chemotherapy has not been shown to be beneficial forappendiceal neoplasms in prospective, randomized trials; it is recommended for adenocarcinomas and goblet-cell adenocarcinomasof stage III or higher, in analogy to the treatment of colorectal carcinoma.

Topics: Humans; Appendix; Appendiceal Neoplasms; Prospective Studies; Hyperthermia, Induced; Adenocarcinoma; Appendectomy

PubMed: 37282595
DOI: 10.3238/arztebl.m2023.0136

Review

Authors: Walid L Shaib, Rita Assi, Ali Shamseddine...

OBJECTIVE

Appendiceal mucinous neoplasms (AMNs) are a rare and heterogeneous disease for which clinical management is challenging. We aim to review the literature regarding modalities of treatment to guide the management of AMNs.

METHODS AND REVIEW CRITERIA

We conducted a PubMed search in February 2016 for English-language publications, using the terms "appendiceal," "appendix," "carcinoma," "cancer," "mucinous," "treatment," "genes," "target," "genomic," and terms listed in the articles' subheadings. Published reports and abstracts from the American Society of Clinical Oncology meetings were also searched.

RESULTS

In this review, we summarize current data and controversies in AMN classification, clinical presentation, molecular alterations, treatment outcomes with regard to cytoreductive surgery, hyperthermic intraperitoneal chemotherapy (HIPEC), and the role of systemic chemotherapy.

CONCLUSION

Appendiceal mucinous neoplasms are a heterogeneous group of tumors with a rising incidence. Treatment is based on stage and histology. Low-grade tumors are treated surgically with resection of the primary site in early stage disease, or peritoneal debulking and HIPEC in patients with advanced stage disease. Treatment of high-grade tumors requires further prospective trials, and options include debulking surgery and HIPEC with or without preoperative chemotherapy. Trials evaluating novel therapies based on the molecular profiling of AMN tumors are needed to evaluate therapeutic options in patients who are not surgical candidates.

IMPLICATIONS FOR PRACTICE

This review provides a reference to guide gastroenterologists, pathologists, surgeons, and oncologists in the management of appendiceal mucinous neoplasms (AMNs), a rare and heterogeneous disease with no consensus on histologic classification or guidelines for treatment algorithms. This review summarizes all AMN classifications and proposes a treatment algorithm based on stage and histology of disease.

Topics: Adenocarcinoma, Mucinous; Antineoplastic Combined Chemotherapy Protocols; Appendiceal Neoplasms; Appendix; Cytoreduction Surgical Procedures; Humans; Hyperthermia, Induced; Neoplasm Staging; Practice Guidelines as Topic; Rare Diseases; Treatment Outcome

PubMed: 28663356
DOI: 10.1634/theoncologist.2017-0081

Review

Authors: M Van de Moortele, G De Hertogh, X Sagaert...

Primary appendiceal cancer is rare and most commonly found incidentally on a surgical specimen after appendectomy for acute appendicitis. This small organ gives rise to different subtypes which are histological and biological distinct. Historically the classification of these tumors has been confusing because of the different nomenclature that is used. This review has broadly classified them into four subgroups: colonic-type adenocarcinoma, mucinous neoplasm, goblet cell carcinoma and neuroendocrine neoplasm. Signet ring cells is not considered as a distinct subgroup but as a histologic feature that can be present in colonic-type adenocarcinoma and mucinous neoplasms. As staging and management of appendiceal tumors depend on these subtypes, an adequate classification of them is important. This review aimed to give an overview of the epidemiology, grading and staging, management and prognosis of these neoplasms. Despite its rarety, specific staging systems and treatment guidelines exist for some subtypes. For other subtypes staging systems and management is extrapolised from colorectal cancer because of the lack of randomised, prospective trials.

Topics: Appendectomy; Appendiceal Neoplasms; Appendicitis; Colorectal Neoplasms; Humans; Prospective Studies

PubMed: 33094592
DOI: No ID Found

Authors: U-F Pape, B Niederle, F Costa...

Topics: Appendiceal Neoplasms; Europe; Humans; Neuroendocrine Tumors

PubMed: 26730583
DOI: 10.1159/000443165

Review

Authors: Phoenix D Bell

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

Topics: Humans; Appendiceal Neoplasms; Adenocarcinoma; Adenocarcinoma, Mucinous; Neoplasm Staging

PubMed: 39214725
DOI: 10.1053/j.semdp.2024.08.005

Authors: Hakan Ozdemir, Zehra Unal Ozdemir, Mehmet O Gul...

BACKGROUND

Histopathological examination of appendectomy specimens may reveal malignancies. Based on these results, either appendectomy is sufficient or sometimes a further treatment protocol can be needed. In this study, malignancy-diagnosed cases on appendectomy specimen were examined.

METHODS

Patients who underwent appendectomy between January 2013 and December 2018 with a pre-diagnosis of acute appendicitis were evaluated retrospectively and those cases with malignancy were included in the study. Patients' age, sex, tumor type, tumor diameter, tumor grade, tumor localization, surgical margin, Ki-67 index, state of lymphovascular invasion, state of peri-neural invasion, and follow-up period duration were recorded.

RESULTS

On examination of 2336 appendectomy specimens, 16 patients (0.7%) were found to have neuroendocrine tumors (NET), 11 patients (0.5%) were found to have low-grade mucinous neoplasm (LAMN), and five patients (0.2%) were found to have primary appendix carcinomas. Appendix tumors usually present with acute appendicitis symptoms. Despite re-operation with right hemicolectomy (RHC) being required in the treatment of adenocarcinoma cases, appendectomy provides adequate treatment in most cases with NET and LAMN. With these tumors, which usually have a benign prognosis, it is important to perform the necessary screening in the postoperative period and not to interrupt follow-up.

Topics: Humans; Appendiceal Neoplasms; Appendicitis; Retrospective Studies; Appendectomy; Neuroendocrine Tumors

PubMed: 38159212
DOI: 10.4103/ijc.IJC_450_20

Review

Authors: Ben Rymer, Rachael O Forsythe, Glen Husada...

INTRODUCTION

Mucocoele of the appendix is rarely encountered but consultant general surgical and trainees must be aware of it as a differential diagnosis, due to the nuances associated with its management. We aimed to provide a comprehensive review of the current literature concerning this rare surgical pathology.

METHODS

Search terms "appendi*", "tumour", "malignancy", "mucino*" and "cystadenoma" were used in combination to identify papers from PubMed. Abstracts and full text were manually reviewed to identify suitable papers.

RESULTS

Full search results included 311 articles. Review of titles and abstracts led to further full text review of 46 articles. Of these 30 were selected for inclusion based on relevance, adequate sample size and recent publication date.

DISCUSSION

Mucocoele of the appendix describes dilatation with associated luminal mucin and can result from benign and malignant processes. It contributes 0.2-0.7% of all appendiceal pathologies. The most common presenting symptoms are abdominal pain and a palpable mass in the right iliac fossa. Computed tomography of the abdomen and pelvis is key in facilitating diagnosis, although CEA and CA19-9 also have a role. The major complication of malignant causes of mucocoele is progression to pseudomyxoma peritonei. Treatment is surgical with or without chemotherapy depending on the underlying cause. Prognosis depends on aetiology.

CONCLUSION

Mucocoele of the appendix is a rare diagnosis. However, given the possibility of neoplastic peritoneal dissemination, it should be considered as a diagnosis, especially in older females with non-specific symptoms similar to appendicitis.

Topics: Abdominal Pain; Appendiceal Neoplasms; Appendicitis; Cecal Diseases; Cystadenoma, Mucinous; Diagnosis, Differential; Female; Humans; Mucocele; Peritoneal Neoplasms; Pseudomyxoma Peritonei; Tomography, X-Ray Computed

PubMed: 25917270
DOI: 10.1016/j.ijsu.2015.04.052

Review

Authors: Richard S Hoehn, Caroline J Rieser, M Haroon Choudry...

Appendiceal neoplasms include a heterogeneous group of epithelial and nonepithelial tumors that exhibit varying malignant potential. This review article summarizes current diagnostic criteria, classification systems, and optimal therapeutic strategies for the five main histopathologic subtypes of appendiceal neoplasms. In particular, the management of epithelial appendiceal neoplasms has evolved. Although their treatment has historically been extrapolated from colon cancer, improved understanding of their unique histopathologic and molecular characteristics and a growing body of published clinical data support a more nuanced approach to their management.

Topics: Appendiceal Neoplasms; Humans; Neoplasms, Glandular and Epithelial

PubMed: 33770459
DOI: 10.1200/EDBK_321009

Authors: Nolan M Winicki, Shannon N Radomski, Yusuf Ciftci...

BACKGROUND

Accurately predicting survival in patients with cancer is crucial for both clinical decision-making and patient counseling. The primary aim of this study was to generate the first machine-learning algorithm to predict the risk of mortality following the diagnosis of an appendiceal neoplasm.

METHODS

Patients with primary appendiceal cancer in the Surveillance, Epidemiology, and End Results database from 2000 to 2019 were included. Patient demographics, tumor characteristics, and survival data were extracted from the Surveillance, Epidemiology, and End Results database. Extreme gradient boost, random forest, neural network, and logistic regression machine learning models were employed to predict 1-, 5-, and 10-year mortality. After algorithm validation, the best-performance model was used to develop a patient-specific web-based risk prediction model.

RESULTS

A total of 16,579 patients were included in the study, with 13,262 in the training group (80%) and 3,317 in the validation group (20%). Extreme gradient boost exhibited the highest prediction accuracy for 1-, 5-, and 10-year mortality, with the 10-year model exhibiting the maximum area under the curve (0.909 [±0.006]) after 10-fold cross-validation. Variables that significantly influenced the predictive ability of the model were disease grade, malignant carcinoid histology, incidence of positive regional lymph nodes, number of nodes harvested, and presence of distant disease.

CONCLUSION

Here, we report the development and validation of a novel prognostic prediction model for patients with appendiceal neoplasms of numerous histologic subtypes that incorporate a vast array of patient, surgical, and pathologic variables. By using machine learning, we achieved an excellent predictive accuracy that was superior to that of previous nomograms.

Topics: Humans; Appendiceal Neoplasms; Male; Female; Middle Aged; Risk Assessment; Aged; Machine Learning; SEER Program; Adult; Algorithms; Prognosis; Retrospective Studies

PubMed: 38494390
DOI: 10.1016/j.surg.2024.02.014

Review

Authors: Konstantinos I Votanopoulos, Perry Shen, Aleksander Skardal...

The early symptoms of appendiceal cancer may mimic the clinical picture of appendicitis. Most patients are diagnosed incidentally during surgical exploration or late when peritoneal or systemic dissemination has already occurred, as colonoscopy rarely will diagnose an appendiceal cancer. Systemic/extraperitoneal metastases are distinctly unusual for appendiceal mucinous lesions.

Topics: Appendiceal Neoplasms; Combined Modality Therapy; Humans; Peritoneal Neoplasms; Treatment Outcome

PubMed: 29935689
DOI: 10.1016/j.soc.2018.02.007