Axillary hibernoma: Radiological and pathological findings of a rare tumour

The hibernoma is a rare hypervascular benign tumour arising from the residual fetal brown fat. It was first described by Merkel in 1906 and named by Gery in 1914. Other names for the same entity are lipoma of immature adipose tissue, lipoma of embryonic fat and fetal lipoma. Approximately 100 cases have been reported, usually in locations where remnants of brown fat can be found in the adult, such as the neck, mediastinum, axilla, abdominal wall; atypical locations like the scalp and thigh have also been described. We present a case of an hibernoma of the right axilla, demonstrating the radiographic and pathological findings.