From the archives of the AFIP. Musculoskeletal malignant fibrous histiocytoma: radiologic-pathologic correlation.

Malignant fibrous histiocytoma (MFH) is a pleomorphic sarcoma, occurring most frequently in the deep soft tissues of the extremities. Primary osseous MFH is less common. MFH is the most common soft-tissue sarcoma of late adult life. Although its imaging appearance is often nonspecific, any deep-seated invasive intramuscular mass in a patient over 50 years of age is most likely an MFH. Cortical involvement by soft-tissue MFH is common, and identification of this finding increases the likelihood of MFH. Prominent fluid components with peripheral nodular enhancement after contrast material administration and lack of adipose elements are suggestive of a specific histologic subtype, myxoid MFH. Osseous MFH shows aggressive bone destruction with cortical involvement and a soft-tissue mass and is located in the diaphysis or metaepiphysis. Lesions in the metaepiphysis may have a less aggressive appearance and do not extend to subchondral bone. Computed tomography and magnetic resonance imaging are vital for preoperative staging and surgical planning and in detecting early recurrence postoperatively.