Comparative immunohistochemistry of malignant fibrous histiocytoma and sarcomatoid carcinoma of the urinary tract

Abstract
An immunohistochemical analysis using antibodies to cytokeratin, epithelial membrane antigen, alpha-1-antitrypsin, alpha-1-antichymotrypsin and factor XIIIa was performed in four cases of malignant fibrous histiocytoma and five cases of sarcomatoid carcinoma in the urinary tract. All cases of malignant fibrous histiocytoma showed positive staining for factor XIIIa, alpha-1-antitrypsin and alpha-1-antichymotrypsin. No case was positive for factor XIIIa, but one case with sarcomatoid carcinoma stained positive for alpha-1-antitrypsin and alpha-1-antichymotrypsin. All cases showed positive staining for cytokeratin and 4 cases with sarcomatoid carcinoma were positive for epithelial membrane antigen, but no cases with malignant fibrous histiocytoma were positive. Immunohistochemical analysis would thus help to distinguish malignant fibrous histiocytoma from sarcomatoid carcinoma of the urinary tract.