Multiple periorbital fibrous histiocytomas: a light and electron microscopic study.

Recurrent, bilateral, multiple, periorbital fibrous histiocytomas occurred in a 62-year-old woman. There were no associated serum lipid abnormalities. Histologically, the tumor was composed of an admixture of lipid-laden histiocytes and fibroblasts with a variable amount of collagen production. In many areas the fibroblasts were arranged in a storiform pattern. No cytologic evidence of malignancy was observed. Ultrastructural studies of the tumor showed histiocytic cells with a variable amount of lipid in the cytoplasm and fibroblasts with mild to moderate collagen production. Differential diagnosis and histogenesis are discussed.