Intra-abdominal necrotic lipoma diagnosed as a paraprostatic cyst by CT scan.

A dog with a history of diarrhea and dyschezia exhibited an oval-shaped, soft-tissue opacity mass in the abdomen on radiographs. CT examination revealed a large fluid-filled structure displacing the urinary bladder, prostate, and colon. The mass had continuity with the prostate; therefore, it was tentatively diagnosed as a paraprostatic cyst. Cytologic examination was performed and the mass was considered a non-inflammatory cyst. However, after surgery, histopathologic examination revealed a necrotic, inflamed cystic lipoma. This case shows that unusual intra-abdominal lipomas may have a cystic appearance.