Primary Eccrine Adenocarcinoma: A Rare but Dangerous Lesion of the Eyelid.

Sweat gland carcinomas can be of eccrine or apocrine origin, with the former being more common in the eyelid. They can also be of three different types, the most common of which is mucin-producing sweat gland carcinoma, which is most often a low-grade malignancy. Here, we report a case of a primary estrogen receptor-positive eccrine adenocarcinoma of the eyelid that clinically presented like a cyst of Moll. Importantly, in our experience with this lesion, this rare malignancy was repeatedly misdiagnosed as less sinister lesions, surgical resection margins of the lesion could be easily underestimated, and close liaison with our general surgical colleagues was vital to exclude more common breast carcinoma. This case highlights the dangers of referral recommendation policies (e.g., procedures of limited clinical value as used by primary care) and the importance of incisional biopsy in the management of periocular lesions.