Malignant fibrous histiocytoma of the larynx after radiotherapy for squamous cell carcinoma

A few cases of malignant fibrous histiocytoma (MFH) of the larynx have been reported to date. All ages may be affected, but the tumor is more prevalen t in the sixth and seventh decade of life. We describe a case of MFH in a 7 1-year-old Italian man who 8 years before underwent a right cordectomy and radiotherapy for squamous cell carcinoma. Recurrent tumor was found to be M FH. The clinico-pathological features of this tumor are presented and the p ossible relationship between radiotherapy and MFH discussed. The neoplasm w as characterized by spindle-shaped atypical cells arranged in a diffuse sto riform pattern. Mitoses were prominent, numerous, and often atypical. Immun ohistochemically, neoplastic cells were strongly positive for vimentin and alpha(1)-antichymotryspin but were negative for cytokeratins and S-100 prot ein. These findings confirmed the diagnosis and excluded possible sarcomato id carcinoma, inflammatory pseudotumor, and a new carcinosarcoma. The risk of sarcoma after radiotherapy for squamous cell carcinoma in the larynx is very low when considering the frequent use of radiotherapy, but long follow -ups are required.