Adenocarcinoma of the appendix, also referred to as nonmucinous adenocarcinoma of the appendix, is an uncommon type of appendiceal epithelial neoplasm. Different from the appendiceal mucinous neoplasms, these tumors share similar epidemiology and pathology with colorectal adenocarcinoma.
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Epidemiology
As colorectal cancer, these tumors commonly occur in elderly patients, often in the 6th decade of life 1.
Clinical presentation
Appendicitis due to a tumoral obstruction of the appendix is a typical presentation (in 70% of cases 2).
Pathology
These tumors differ from polyps and adenomas, which are confined to the mucosal layer and do not invade the muscularis mucosae but are thought to arise from adenomas in virtually all cases 2. They are classified as well, moderately, and poorly differentiated 1.
Radiographic features
Cross-sectional imaging usually shows an ill-defined soft tissue mass in the appendix, which can invade adjacent structures 3.
The appearance of appendiceal adenocarcinoma with early obstruction is typically that of appendicitis, consisting of a thickened, inflamed appendix with non-filling with contrast material and periappendiceal fat stranding 2-3.
Appendiceal cystadenocarcinoma can present as an appendiceal mucocele 2.