Angiomatoid Malignant Fibrous Histiocytoma

This study reports the immunohistochemical, ultrastructural, and flow cytometric find ings of two cases of angiomatoid malignant fibrous histiocytoma that developed in the subcutis of the temple of a 10-year-old girl and the shoulder region of a 5-year- old boy. The neoplasm of the temple developed a local recurrence 6 months after the initial excision. Both patients were well and free from tumor at 24 months and 12 months, respectively. Immunohistochemically, many tumor cells of both cases posi tively expressed vimentin, desmin, HHF-35, and KP1. In one case many tumor cells also showed lectin binding for ulex europaeus agglutinin 1, and the other case pre sented ultrastructural features of immature endothelial cells. All tumors, including the recurrent lesion, were diploid. Divergent antigenic phenotypes along with many types of cells were considered; including myogenic cell, fibroblastic cell, and immature endo thelial cell. This study suggests that angiomatoid malignant fibrous histiocytomas show a wide range of pluripotential differentiation. Int J Surg Pathol 2(2):99-104, 1994