Postinflammatory pseudotumors of the lung: fibrous histiocytoma and related lesions.

Three cases of pulmonary fibrous histiocytoma, sometimes known as xanthogranuloma and fibrous xanthoma, are described. The lesion is part of a spectrum of diseases known as postinflammatory pseudotumors of the lung. It is usually discovered on routine radiographic examination on which it appears as a well circumscribed mass, and it usually has a benign course. The microscopic findings upon which diagnosis is based, the theories of origin, and previously reported cases are discussed.