Cutaneous lymphadenoma with ductal differentiation

Cutaneous lymphadenoma (CL) is a recently described neoplasm of unknown histogenesis. Histologically, these tumors typically present as well-circumscribed nodules with scant or no epidermal connections. They are composed of multiple rounded lobules of basaloid cells with some degree of peripheral palisading. These epithelial lobules characteristically show a dense lymphoid infiltrate within them. In cases of CL previously described, there was no obvious adnexal differentiation except for isolated cells showing apparent sebaceous differentiation or hints of follicular differentiation. We report two typical cases of CL that were studied histologically and immunohistochemically. In some of the tumor lobules, there were foci of ductal differentiation, with luminal positivity for CEA and EMA. We postulate that some CL represent a form of immature sweat gland tumor with ductal differentiation.