A case of malignant fibrous histiocytoma of the lung arising as a third primary tumor

A case of primary malignant myxoid fibrous histiocytoma of the lung presenting as a solitary lung nodule in a 61-year-old man is presented. This tumor arose in a patient with a transitional-cell carcinoma of the urinary bladder and a well differentiated squamous-cell carcinoma of the larynx, The differential diagnosis between a primary lung tumor versus a solitary metastasis is difficult and was supported by histological features and the lack of epithelial properties proved by immunohistochemistry. Tobacco was the only etiologic factor known in the patient.