Familial syringoma. Case history and application of monoclonal anti-eccrine gland antibodies.

We studied a family with dominantly inherited eruptive syringoma. The father and the older daughter had chest and neck as well as eyelid lesions. The chest lesions seemed to develop continuously by new formation of eccrine germlike budding from the epidermis. Monoclonal antikeratin antibody EKH4, which predominantly labels the basal layers of the epidermis, stained positively in the cordlike epithelial structure and peripheral cells of the walls of cystic lesions. Staining with EKH6, which recognizes normal eccrine secretory and ductal structures--particularly luminal borders--was positive along the luminal borders of the cystic lesions; staining with EKH5, which labels eccrine secretory portion, was entirely negative in the lesions. These findings further supported the theory that syringoma of the eyelids and eruptive syringoma, which mainly involves the anterior neck and upper chest, are essentially the same tumor and that these appendage tumors are of eccrine ductal differentiation.