Osteolipoma in the Forearm

A case of left distal forearm and wrist osteolipoma in a 56 year old female is reported. The patient presented with a 3 year history of nontender left wrist mass. Radiographs demonstrated a lobulated mass of mixed low density and calcifications, not adjacent to and with no connection to underlying bone. Ultrasound showed a spheroid hyperechoic lesion with internal heterogeneity and rim of calcifications. Magnetic resonance imaging revealed a lesion with predominantly fat characteristics on T1 weighted and T2 weighted sequences, with rim of peripheral calcification and specks of internal calcification. Histological examination after excision of the mass showed the lesion to be an osteolipoma. Osteolipoma is a rare variant of lipoma with osseous metaplasia and should be considered in the differential of a fat containing mass with ossification.