MediAI

  Executive Answer  A markedly dilated, cystic appendix with mural calcification should not be dismissed as simple appendicitis or nonspecific fluid collection. In this case, a man in his early 60s presented with acute abdominal pain, and ultrasound and contrast-enhanced CT demonstrated a large pear-shaped appendiceal lesion with a thick wall, mixed internal attenuation, and calcification. The final pathology showed mucinous adenocarcinoma arising in association with high-grade appendiceal mucinous neoplasm (HAMN), with invasion into the muscularis propria. The key radiologic lesson is simple: when an enlarged appendix becomes cystic, the radiologist must determine not only whether it is dilated, but why—and whether there is evidence of invasive disease or peritoneal spread. Why This Case Matters Acute abdominal pain naturally directs clinical attention toward common emergency diagnoses, particularly acute appendicitis. That diagnostic reflex is appropriate in many patie...