Demonstration of alpha-1 antichymotrypsin in tumours of supposed bibroblastichistocytic origin using the immunoperoxidase technique

ABSTRACT

Using the immunoperoxidase [PAP] technique, 28 cases of fibrohistiocytic tumors were stained for alpha-1-antichymotrypsin [A1ACT], a histiocytic marker, and S-100 protein, a marker for Schwann cells. A1ACT was demonstrated in 12 of 13 cases of malignant fibrous histiocytomas [MFH], in 6 of 9 cases of dermatofibrosarcoma protuberans [DFP] and in 4 of 6 cases of dermatofibroma [DF]. None of these tumors stained positively for S-100 protein. A1ACT is found to be a useful and reliable marker for malignant fibrous histiocytoma. The presence of alpha-1 antichymotrypsin and the absence of S-100 protein in DFP and DF support the concept that these neoplasms are parts of the spectrum of fibroblastic-histiocytic tumors and excludes their neurogenic origin