Giant Cell Fibroblastoma: A Case Report and lmmunohistochemical Comparison with Ten Cases of Dermatofibrosarcoma Protuberans

A 7 year old boy with giant cell fibroblastoma (GCF) of the skin and subcutaneous tissue of the right chest wall is described. To date, the histogenesis of GCF has not been clarified. The reason for the diversity of immunohistochemical data among various authors may be because the specimens studied were from only part of the lesion, or reduction of antigenicity through the preparation process. However, our findings based on studies of many specimens from various parts of the tumor for accurate immunohistochemical evaluation suggest that GCF may be a myofibro histiocytic tumor. Recently, the suggestion that GCF is a juvenile form of dermatofibrosarcoma protuberans (DFSP) has been reported. In addition to the present case, we performed immunohistochemical examination of 10cases of definitely diagnosed DFSP for comparison. The immunohistochemical characteristics of these two neoplasms were concordant. However, from clinical and morphological viewpoints, it seems premature to recognize GCF as a juvenile form of DFSP. Acta Pathol Jpn 41: 552–560, 1991.