Abstract
We experienced two cases of nodular hidradenoma, which showed distinct differentiation patterns; poroid hidradenoma and apocrine hidradenoma. Case 1 was a 1.5cm-sized nodule without itch or pain appeared on the back of a 81-year-old man. We diagnosed the tumor as an apocrine hidradenoma because there were many clear cells intermingled with epidermoid cells which showed decapitation secretion. Case 2 was a 3cm-sized nodule on the back of a 48-year-old man. This case was a poroid hidradenoma showing eccrine differentiation because most of the composing cells were poroid cells and cuticular cells. However, there were also many mucinous cells and clear cells, which indicated apocrine differentiation. Our cases suggested that, in nodular hidradenoma, not only apocrine hidradenoma, but also poroid hidradenoma could show some features toward apocrine differentiation.
