Inflammatory myofibroblastic tumor of the larynx. A clinicopathologic study of eight cases simulating a malignant spindle cell neoplasm.

BACKGROUND: Inflammatory myofibroblastic tumors of the larynx are uncommon lesions that easily may be misinterpreted as malignant epithelial or mesenchymal spindle cell neoplasms.

METHODS: Eight cases of laryngeal inflammatory myofibroblastic tumors were identified from the files of the Otolaryngic Tumor Registry--Armed Forces Institute of Pathology. Clinical records and follow-up were available in all cases. The light microscopic features (hematoxylin and eosin and special histochemical stains) were evaluated in all cases; immunohistochemical analysis was performed in the seven cases with available paraffin blocks; in four cases ultrastructural analysis was done.

RESULTS: The patients included five males and three females ranging in age from 19-69 years (median, 59 years). Presenting symptoms included hoarseness, dysphonia, or rapidly progressive stridor with the duration of symptoms ranging from 10 days to 4 months. The most common site of involvement was the true vocal cord. The lesions appeared as polypoid or pedunculated masses. Histologically, the cellularity of the lesions varied, consisting of spindle-shaped to stellate cells with no consistently discernible growth pattern, in a fibromyxoid stroma that included a mixed inflammatory cell infiltrate. Features suggesting a malignant cellular infiltrate were not present. The spindle-shaped cells had consistent immunoreactivity with vimentin, muscle specific actin, and smooth muscle actin. Ultrastructurally, intracytoplasmic microfilaments were identified. In seven of the patients, conservative but complete excision of the lesion was curative; these patients have been free of disease over periods ranging from 12 to 36 months. In one patient, the lesion recurred twice over a 2-year period and ultimately required a total laryngectomy. This patient died of unrelated causes.

CONCLUSIONS: Inflammatory myofibroblastic tumors of the larynx are unusual benign proliferative lesions. Conservative surgical management is advocated and is curative. Recurrence is rare, but metastases disease or death attributable to these lesions is not.