[Retroperitoneal hibernoma]

We report a new case of retroperitoneal hibernoma. Hibernoma is a rare, benign soft tissue tumor whose constituent cells resemble those of brown fat tissue, which is present in human fetus and newborn infant and it gradually diminishes in quantity throughout adult life. Retroperitoneal location is unusual. Differential diagnosis with the liposarcoma (the most frequent tumour on this location) is based on the high vascularity of the hibernoma. Total resection of the tumour can achieve complete cure without recurrence nor metastasis.