Malignant fibrous histiocytoma of the lung

Malignant fibrous histiocytoma (MFH) is among the most common soft tissue sarcomas of adult life, but rarely occurs elsewhere. We report an example of primary MFH of the lung and review 15 previously reported acceptable cases with current follow-up information. Histologically, the tumor in our case was pleomorphic with storiform and fascicular areas. Tumor cells showed positive immunostaining for alpha,-antitrypsin, alpha,-antichymotrypsin, and vimentin. Stains for desmin, cytokeratin, myoglobin, epithelial membrane antigen, SlOO protein, and lysozyme were negative. Electron microscopic study showed histiocyte-like, fibroblast-like, intermediate, and undifferentiated tumor cells. A variety of methods were used to treat these patients. Two patients survived for 5 or more years, two were alive and well at 8 and 12 months, respectively, two were alive with metastatic tumor at 3 and 18 months, respectively, and ten patients died of tumor, with an average survival of 1 year. Cancer 61:137-145, 1988. ALIGNANT FIBROUS histiocytoma (MFH) is one of M the most common soft tissue sarcomas of older adults, with a peak age incidence in the sixth and seventh decades of life.'.2 It most frequently involves the extremities, retroperitoneum, and trunk. Primary MFH of the lung is rare, with leiomyosarcoma and fibrosarcoma being the most commonly reported primary pulmonary sa~comas.~'~ By routine light microscopic examination, MFH may be difficult to distinguish from leiomyosarcoma, fibrosarcoma, pleomorphic liposarcoma, pleomorphic rhab domyosarcoma, malignant schwannoma, spindle-cell and anaplastic carcinoma, and malignant melanoma, such that immunohistochemical and electron microscopic techniques may be required for the diagnosis. We report an example of primary MFH of the lung, confirmed by electron microscopic and immunohistochemical studies, and review the previously reported