Hibernoma: A case report and discussion of a rare tumor

Abstract

Hibernomas are benign soft tissue tumors, derived from brown fat. While tumors arising from white adipose tissue are among the most common soft tissue lessions, hibernomas are among the rarest, with only 120 cases reported in the world's literature so far. This tumor was first described by Merkl in 1906 as being composed of brown adipose tissue. The term hibernoma was proposed in 1914 by Gery because of its morphologic similarity to the cells of the so-called hibernating glands of animals. Most hibernomas occur in sites where brown fat persists beyond fetal life (usually in the interscapular region or thigh), but they also occur in sites where brown fat is usually absent. Hibernomas are slow-growing, painless neoplasms which do not recur. Total excision is advocated, as there is no known malignant potential. We describe a 21-year-old male with interscapular hibernoma, and emphasize the necessity of differentiation from well-differentiated liposarcoma.