Giant Cell Fibroblastoma, Dermatofibrosarcoma Protuberans, and Fibrosarcomatous Change

Giant cell fibroblastoma is a classified as a fibrohistiocytic tumor of intermediate malignancy. There is sufficient evidence to support a histogenetic relationship to dermatofibrosarcoma protuberans. Although giant cell fibroblastoma often is referred to as the “juvenile variant” of dermatofibrosarcoma protuberans, giant cell fibroblastoma can occur in adults, and, contrarily, dermatofibrosarcoma protuberans can occur in infants and children. Some tumors have overlapping histologic features, and both of these tumors are characteristically CD34 positive. Moreover, both tumors share a characteristic cytogenetic aberration, t(17;22). Fibrosarcomatous change occurs in up to 10% of dermatofibrosarcoma protuberans but also has been described in rare examples of giant cell fibroblastoma. Although this histologic change clearly imparts a more aggressive clinical behavior, adequate initial surgical excision limits the morbidity and mortality of this histologic progression.