Perforated Appendicitis as a Herald of Appendiceal Adenocarcinoma: A Case Report and Literature Review.

Appendiceal adenocarcinoma is a highly uncommon gastrointestinal tumor that can have severe consequences if not identified or properly treated. These malignancies are often diagnosed incidentally after appendectomy through histopathological evaluation of the appendix. Moderate- or poorly differentiated tumors frequently warrant completion right hemicolectomy followed by adjuvant chemotherapy. We present the case of a 76-year-old male with a history of hypertension, benign prostatic hyperplasia, and seborrheic keratosis who was admitted for management of a ruptured appendix associated with an intra-abdominal abscess. He improved symptomatically after undergoing CT-guided abscess drainage and receiving antibiotics targeting bowel flora. However, a formal diagnosis of appendiceal cancer was established when histopathology from interval appendectomy seven weeks later revealed invasive adenocarcinoma with extensive mucin production invading through the appendiceal wall and obstructing the distal appendix. He subsequently underwent completion right hemicolectomy, with histopathology demonstrating no lymphatic invasion and clear surgical margins. At the time of this report, he was preparing to begin a 5-fluorouracil-based chemotherapy regimen. This case highlights perforated appendicitis as a potential harbinger of appendiceal carcinoma and reviews the diagnostic and therapeutic considerations for mucinous appendiceal adenocarcinomas, emphasizing the importance of recognizing malignancy and intervening promptly in the context of perforated, acute appendicitis.