Spiradenoma associated with apocrine adenoma component.

We present a case of spiradenoma associated with an apocrine adenoma component. The transitions between the spiradenoma and apocrine adenoma components were gradual. It could be observed that the small dark cells seen at the peripheries of the cell nodules of the spiradenoma component were replaced by the peripheral flat myoepithelial cell layer in the apocrine component. Similarly, the large pale cells within the centers of the cell nodules of the spiradenoma component were replaced by the brightly eosinophilic secretory cells with decapitations secretion in the apocrine component of the tumor. The reported case proves that at least some spiradenomas are tumors with distinct apocrine instead of eccrine differentiation.