Papillary hidradenoma of the eyelid margin: clinical and immunohistochemical observations further supporting an apocrine rather than an eccrine origin.

A 46-year-old woman was evaluated for a "recurring papilloma" of the left medial upper eyelid margin. Beneath the papillary lesion medial to the punctum was a 5-mm diameter cutaneous mass thought to be cystic. After excisional biopsy, histopathologic analysis documented the presence of an epidermal keratinizing squamous papilloma surmounting a circumscribed dermal papillary hidradenoma composed of deeply eosinophilic columnar cells. Additionally, there was intraductal proliferation of tumor extending toward a subclinical poral opening through the epidermis. Immunohistochemistry proved the apocrine nature of the benign, non-cystic lesion by virtue of its nuclear androgen receptor and cytoplasmic gross-cystic disease fluid protein-15 positivity, along with its smooth muscle actin-positive myoepithelial layer. This and prior cases establish that apocrine tumors, both benign and malignant, are strictly localized at or near the eyelid margin where only apocrine glands are found. These tumors are more often papillary than solid adenomas, and most exceptionally can be malignant. We review the differential diagnosis of simulating eccrine eyelid tumors. We recommend wide local excision for benign lesions, in view of possible intraductal extension that can be eccentric to the main tumor and the miniscule potential for malignant transformation.