Primary Appendiceal Adenocarcinoma Masquerading as Acute Appendicitis: A Case Report.

Primary adenocarcinoma of the appendix is a rare neoplasm, and a large number are found incidentally during abdominal imaging and operations with other indications. This report examines a case of primary appendiceal adenocarcinoma discovered incidentally following a seemingly routine laparoscopic appendectomy in a 69-year-old male. The patient presented with atypical signs of acute appendicitis, including a history of waxing and waning right lower quadrant pain without anorexia, fever, or chills over five days. After undergoing laparoscopic appendectomy, histopathologic analysis of the appendix specimen revealed invasive adenocarcinoma. This case emphasizes the importance of maintaining a high index of suspicion for appendicitis versus appendiceal neoplasm in older adults presenting with atypical signs and symptoms.