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 prevalent in the sixth and seventh decade of life. We describe a case of MFH in a 71-year-old Italian man who 8 years before underwent a right cordectomy and radiotherapy for squamous cell carcinoma. Recurrent tumor was found to be MFH. The clinico-pathological features of this tumor are presented and the possible relationship between radiotherapy and MFH discussed. The neoplasm was characterized by spindle-shaped atypical cells arranged in a diffuse storiform pattern. Mitoses were prominent, numerous, and often atypical. Immunohistochemically, neoplastic cells were strongly positive for vimentin and alpha1-antichymotrypsin but were negative for cytokeratins and S-100 protein. These findings confirmed the diagnosis and excluded possible sarcomatoid 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.