Perigastric appendagitis mimicking biliary colic: Recognition of the central dot sign on CT.

Perigastric appendagitis is a rare form of intraperitoneal focal fat infarction (IFFI) caused by torsion or venous thrombosis of fatty appendages adjacent to the stomach. Because of its unusual location and nonspecific clinical presentation, it may mimic gastric, biliary, or pancreatic disease, potentially leading to unnecessary investigations or intervention if not recognized on imaging. We report a 47-year-old woman who presented with four days of diffuse abdominal pain. An outside ultrasound demonstrated a small gallbladder calculus, initially directing the diagnostic workup toward biliary pathology. However, contrast-enhanced CT revealed a well-defined oval fat-density lesion in the epigastrium, anterior to the gastric body, demonstrating both a central dot sign and a hyperattenuating rim sign. No internal enhancement was identified, with surrounding inflammatory fat stranding and minimal pelvic free fluid. Follow-up ultrasound demonstrated expected evolution into a heterogeneous avascular lesion consistent with resolving fat necrosis. The patient was successfully managed conservatively with complete resolution of symptoms. This case highlights the importance of recognizing the characteristic CT features of perigastric appendagitis, particularly when incidental findings such as gallstones may divert attention from the correct diagnosis.