Case reports in gastrointestinal medicine
Retroperitoneal Hibernoma Presenting as a Gastrointestinal Surgical Diagnostic Challenge: A Rare Benign Lipomatous Tumor and Literature Review
By Fonseca GM, de Lima LGCA and Machado MCC.
Abstract
Background
Hibernoma is an uncommon benign adipocytic neoplasm showing differentiation toward brown fat. Although it usually occurs in anatomical sites where residual brown adipose tissue persists, retroperitoneal involvement is particularly uncommon, with fewer than 60 cases reported.
Case presentation
A 54-year-old man was found to have a retroperitoneal mass incidentally during a routine physical examination. CT and MRI demonstrated a 15-cm homogeneous fat-containing lesion without radiological evidence of local invasion. Complete surgical excision was performed. Histopathological examination showed univacuolated and multivacuolated adipocytic cells without atypia. The tumor was positive for S-100 and CD10, and fluorescence in situ hybridization showed no MDM2 amplification, supporting the diagnosis of hibernoma. Recovery was uneventful, and the patient was discharged on Postoperative Day 7.