MFH: An Aggressive Cancer Rarely Seen in Head and Neck

Malignant fibrous histiocytoma (MFH) is the most common soft tissue sarcoma. Most of the time, it arises in the extremities and retroperitoneum, but it also occurs in the facial sinuses, nasal and oral cavities, nasopharynx, and soft tissues of the neck.

It is relatively uncommon in the head and neck (about 5 percent of the total), but when it does occur, it is usually in soft tissue or, rarely, in the mandible, said Erich Sturgis, MD, MPH, Associate Professor of Head and Neck Surgery and Epidemiology at M. D. Anderson Cancer Center in Houston. There are only about 500 sarcomas of the head and neck each year in the United States.

The disease occurs more commonly in whites than in blacks or Asians, and males develop it about twice as often as females. MFH has a wide age range (10-90 years), but it is most common from age 50 to 70.

Pathophysiology

MFH has variable pathophysiology and many subtypes. Tumors contain both fibroblast-like and histiocyte-like cells in varying proportions, giving rise to five major subtypes: storiform/pleomorphic (most common); myxoid; giant cell; inflammatory (usually not seen in the head and neck); and angiomatoid-although the last may be a distinct, more indolent, disease. Dr. Sturgis said that most sarcoma pathologists think that MFH is poorly differentiated.

However, said David W. Clark, MD, of the Department of Otolaryngology-Head and Neck Surgery at University of Texas Health Science Center at Houston, Some people argue that the histiologic subtypes are no longer pertinent and that MFH represents a group of unclassifiable sarcomas, and hence is synonymous with pleomorphic undifferentiated sarcoma.

Myogenically differentiated tumors that suggest muscle origin can behave more aggressively, so a thorough pathology investigation is necessary to ensure accurate classification.

The cause of MFH is unknown, but it is believed that a genetic abnormality on the short arm of chromosome 19 or loss of chromosome 13 may play a role.

The disease also has been linked to radiation treatment for breast cancer, retinoblastoma, Hodgkin’s disease, nasopharyngeal carcinomas, and other head and neck malignancies.

Diagnosis

Patients often present with a painless soft tissue mass in the neck that, before biopsy, may be confused with lymphomas, other soft tissue sarcomas, and metastatic carcinomas. Those on the scalp are often mistaken for desmoplastic melanomas or atypical fibroxanthomas. Those arising in the nose, nasopharynx, and paranasal sinuses can be confused with other sinonasal malignancies.