Peritoneal chronic inflammatory mass formation due to gallstones lost during laparoscopic cholecystectomy.

We here describe the radiologic findings of peritoneal chronic abscess formation due to gallstones lost within the peritoneum during laparoscopic cholecystectomy (LC). A radiologic workup 7 months after LC revealed a soft-tissue mass with contrast enhancement, harboring internal necrosis and punctate calcium located in the Morrison's pouch. The mass exhibited restricted water molecule diffusion, absence of fat deposition, and increased F-18 fluorodeoxy-D-glucose uptake, thus mimicking a malignant tumor. The biopsy revealed an inflammatory granuloma. Another patient with similar findings was treated with percutaneous abscess drainage. Thus, radiologists should be aware of this disease condition and its imaging findings.