Immunophenotypic aspects of cylindroma and nodular hidradenoma

Background Some adnexal tumours have many controversies about their histogenesis. Objectives To evaluate the eccrine and/or apocrine differentiation phenotype in cases of cylindroma and clear cell hidradenoma with CD15 and p63 antibodies. Methodology Slides and blocks of six cases of cylindroma and seven cases of nodular hidradenoma (clear cells) were analyzed by the technique of immunohistochemistry with CD15 and p63 antibodies. Results In all cases of cylindroma we obtained negative results for CD15 antibody and positive for p63 antibody. In five of seven cases of nodular hidradenoma (clear cell), we could easily observe clear cells between 20% and 50% of tumour cells. In the two other cases, cystic lesions were present and occasional clear cells could be seen. The reaction with CD15 antibody was positive in granular and cytoplasmic pattern in six of seven cases, especially in cells with suggestive clear cytoplasm in lower proportion than this clear cells could be seen in haematoxylin and eosin. The positivity for p63 antibody, nuclear pattern, was observed in six of seven cases, in the major part of tumour cells. In only one case, the positivity was in 20% of cells. Limitation Samples are in small number because these are relatively rare tumours. Conclusions The present study suggests eccrine origin for both tumours: cylindroma and clear cell hidradenoma.