appendiceal mucinous adenocarcinoma
Mucinous adenocarcinomas of the appendix are at the malignant end of the spectrum of the mucinous neoplasms that affect the cecal appendix.
For the mucinous carcinomas involving the remainder of the colon, please refer to the article on mucinous carcinoma of the colon.
Epidemiology
The peak incidence is in the 6 and 7 decades . Associations with other colonic neoplasms and chronic ulcerative colitis have been reported .
Clinical presentation
Symptoms are much more likely to manifest than in the other more indolent appendiceal neoplasms (e.g. adenoma or neuroendocrine tumors). The spectrum of symptoms varies from vague abdominal pain, nausea, vomiting, and weight loss, to a palpable mass, abdominal distension, and acute appendicitis .
Pathology
Considerable controversy still exists regarding mucinous neoplasms of the appendix pathologic classification and nomenclature . 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 behavior has been proposed and since then the term mucinous adenocarcinoma should be reserved for those mucinous tumors with infiltrative invasion beyond the muscularis mucosa .
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 tumor has more than 50% of cells showing the classical signet ring morphology .
Radiographic features
Fluoroscopy
Barium enema
Non-specific signs may indicate a tumoral lesion adjacent to the cecum, including the non-filling of the appendix, a submucosal mass lesion at the cecal pole, and an extraluminal compression of the cecum .
Treatment and prognosis
Staging and management of these are different from those of colorectal carcinoma, please refer to the appendiceal mucinous neoplasms TNM staging for further details.
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