Spiradenocarcinoma: a clinicopathologic and immunohistochemical study of three cases.

Three cases of malignant transformation within spiradenoma are described. All of them occurred close to the elbow. In every case we found a benign component, characteristic of the spiradenoma, and a structure of carcinoma, which in some areas showed transition into the spiradenoma. In one case the structure of the spiradenocarcinoma resembled that of the spiradenoma, whereas in the remaining two cases adenocarcinoma was the malignant counterpart of the tumor. We performed immunohistochemical studies and revealed various intensities of expression of cytokeratins and epithelial membrane antigen and a dearth of S-100 protein, vimentin, and carcinoembryonic antigen in the examined cases of spiradenocarcinoma.