Cutaneous lymphadenoma: report of 2 cases

Cutaneous lymphadenoma is a recently described tumor with a distinctive histological picture associating a basaloid epithelial proliferation and intraepithelial lymphocytes; it seems to represent a benign adnexal neoplasm of uncertain histogenesis. We documented 2 additional examples of cutaneous lymphadenoma with typical histological features; the contiguity of some tumor lobules with preexisting follicular structures was noted. In 1 case, a cutaneous osteoma was present below the tumor. On immunostainings, S-100 protein revealed numerous dendritic intraepithelial and stromal cells. The basaloid proliferation was positive for broad-spectrum keratin antibodies, but negative for KL1 antibody. In addition, several areas were positive for involucrin within tumor lobules. Our findings are consistent with a pilosebaceous origin of cutaneous lymphadenoma.