Mucinous adenocarcinomas of the appendix are on the malignant end of the spectrum of the mucinous neoplasms that affect the caecal appendix.
Peak incidence in the 6th and 7th decades 1,3. Associations with other colonic neoplasia and chronic ulcerative colitis have been reported 1.
Symptoms are much more likely to happen than in the other more indolent appendiceal neoplasms (e.g. adenoma or neuroendocrine tumours). The spectrum of symptoms varies from a vague abdominal pain, nausea, vomiting, and weight loss, to a palpable mass, abdominal distension, and acute appendicitis 1,3.
Considerable controversy still exists on mucinous neoplasms of the appendix pathologic classification and nomenclature 1. According to a panel of specialist review in 2016, a new nomenclature and classification for the appendiceal mucinous neoplasms based on their histologic type and biologic behaviour has been proposed and since then the term mucinous adenocarcinoma should be reserved for the mucinous tumours that have an infiltrative invasion beyond the muscularis mucosa 1,2.
An adenocarcinoma is defined as mucinous when extracellular mucin corresponds to more than 50% of the lesion. The signet ring cell carcinoma variant occurs when a tumour has more than 50% of cells showing the classical signet ring morphology 1,2.
Nonspecific signs may indicate a tumoural lesion adjacent to the caecum, including the non-filling of the appendix, a submucosal mass lesion at the caecal pole, and an extraluminal compression of the caecum 1.
Treatment and prognosis
- 1. Tirumani SH, Fraser-Hill M, Auer R, Shabana W, Walsh C, Lee F, Ryan JG. Mucinous neoplasms of the appendix: a current comprehensive clinicopathologic and imaging review. Cancer imaging : the official publication of the International Cancer Imaging Society. 13: 14-25. doi:10.1102/1470-7330.2013.0003 - Pubmed
- 2. Carr NJ, Cecil TD, Mohamed F, Sobin LH, Sugarbaker PH, González-Moreno S, Taflampas P, Chapman S, Moran BJ. A Consensus for Classification and Pathologic Reporting of Pseudomyxoma Peritonei and Associated Appendiceal Neoplasia: The Results of the Peritoneal Surface Oncology Group International (PSOGI) Modified Delphi Process. The American journal of surgical pathology. 40 (1): 14-26. doi:10.1097/PAS.0000000000000535 - Pubmed
- 3. Leonards LM, Pahwa A, Patel MK, Petersen J, Nguyen MJ, Jude CM. Neoplasms of the Appendix: Pictorial Review with Clinical and Pathologic Correlation. Radiographics : a review publication of the Radiological Society of North America, Inc. 37 (4): 1059-1083. doi:10.1148/rg.2017160150 - Pubmed
The appendix can be affected by numerous inflammatory, infectious and neoplastic conditions:
- appendiceal mucocele
- appendiceal intussusception
neoplasms of the appendix
- appendiceal epithelial neoplasms
- appendiceal neuroendocrine tumours
- appendiceal lymphoma