Benign fibrous histiocytoma of the skin. A morphologic study of 290 cases.

Two hundred and ninety cases of benign fibrous histiocytoma of the skin are reviewed. Their frequency, distribution according to age, sex and sites, and the architectural and cytological features of the tumors are analyzed. Ninety two cases (31,7%) were male and 198 cases (68,3%) were female. The tumors were most frequently found between second and fourth decades and located mainly in the extremities. Twenty three cases were clinically diagnosed as malignant tumors. Five cytological patterns of benign fibrous histiocytoma of the skin are described: fibrous, vascular, xanthomatous, pleomorphic and giant cell histiocytoma. Their probable histogenesis and the spectrum of morphological variants are discussed.