Mucinous adenocarcinoma of the appendix presenting as acute appendicitis: a case report.

Mucinous adenocarcinoma of the appendix (MAA) is a rare primary malignancy with an incidence of 0.01-0.2% and often presents as acute appendicitis. We present a case of a 61-year-old male who initially presented with right iliac fossa pain, worsening over 3 days, accompanied by appetite loss but no other symptoms. The patient's history included a splenectomy and epilepsy. Physical examination and computed tomography scan suggested a picture of acute appendicitis. He underwent an emergency laparoscopic appendectomy that was converted to open right hemicolectomy due to the mass's adherence to the cecum. The mass, at the cecum, originating from the appendix, measured 10 × 7 × 7 cm. Pathology confirmed a moderately differentiated MAA. Accurate diagnosis requires a combination of imaging and histopathology. The patient recovered well and was discharged on Day 6 postoperatively. We aim to highlight the importance of distinguishing MAA from acute appendicitis and the need for careful preoperative evaluation.