Thyroid regional metastasis from a giant cell malignant fibrous histiocytoma of the larynx in a patient with history of trichinellosis and tuberculosis.

Sarcomas represent less than 1% of malignant laryngeal tumors and giant cell malignant fibrous histiocytoma is exceptionally rare. Diagnosis is histologically based and immunohistochemistry allows differentiation from other fibro-histiocytic neoplasms. We present the case of a 53-year-old male patient with positive medical history for trichinellosis and tuberculosis, and a laryngeal tumor invading the thyroid and causing respiratory distress by airway obstruction. Total laryngectomy and thyroidectomy were performed followed by thyroxine replacement therapy and radiotherapy. Histologically, the tumor consisted of spindle shaped cells with prominent mitoses, and abundant, osteoclast-like, multinucleated giant cells. Similar lesions were identified in the thyroid, adipose and muscular tissues. Parasitic elements were present in muscles. Tumoral cells showed positive immunostaining for Ki67 (40-50%) and vimentin and negative for AE1/AE3, CD31, S100 and myoglobin; the giant multinucleated cells were CD68-positive. Chronic infection might have had a pathogenic significance.