Primary liposarcoma of bone: light and electron microscopic study.

The case history of a patient with primary liposarcoma of the humerus associated with a schwannoma of the radial nerve in the arm is described. Ultrastructurally, the neoplasm showed multiple and varied lipid droplets, dilated RER, mitochondria with electron-dense matrix, and microfilaments as the most prominent features. It is concluded, based on these ultrastructural observations, that liposarcoma of the bone is similar to pleomorphic liposarcoma arising in the soft tissues. This is the first ultrastructural study of a primary liposarcoma of the bone and the first reported association of this tumor with a schwannoma. The possible pathogenetic relationship between both tumors remains unknown.