[A case of primary malignant fibrous histiocytoma of the right lung].

A malignant fibrous histiocytoma (MFH) is the most common soft tissue sarcoma found in adults, but a primary MFH of the lung is very rare. A chest X-ray taken of a 73-year-old man revealed a massive lesion in the right upper lobe, and a subsequent right upper lobe lobectomy uncovered a soft, light yellow tumor in the right S3 area, measuring 2.8 x 2.6 x 1.7 cm. Histologically, the tumor manifested a typical storiform pattern of spindle-sharp cells with no sign of a myosarcoma. As no abnormal lesion was detected in the abdomen and extremities, the tumor was diagnosed as a primary MFH of the lung.