Benign Mesenteric Lesion Presenting with Features of a Malignant Mass.

Encapsulated fat necrosis (EFN), most commonly, is an asymptomatic entity and is often found incidentally in images. However, in the abdomen, it may present as an acute abdomen. Mesenteric fat necrosis is part of a larger disease spectrum called collectively mesenteric sclerosis. It results in forming of a mass that can be confused with other pathologies such as liposarcoma, carcinoma of the cecum, and other more benign conditions such as appendagitis of the epiplon. We present the case of an 82-year-old male who presented with an asymptomatic right lower quadrant mass with concerning computed tomography findings with no previous abdominal surgery or trauma history. Diagnosing EFN is crucial as it can mimic bowel cancer and immune-related mesenteric pathology such as sclerosing mesenteritis, the management of which is far more extreme and aggressive than EFN.