Tubular apocrine adenoma of the eyelid – A case report and literature review

Tubular apocrine adenoma is a rare benign adnexal neoplasm most commonly identified in the scalp, composed of a dermal proliferation of apocrine tubules in a background of hyalinized stroma. Tubular apocrine adenoma can be a component of various sweat gland tumors and can also morphologically overlap with other sweat gland neoplasms. Isolated tubular apocrine adenoma arising in the glands of Moll is exceedingly rare, with only 4 previously reported cases. We present a 63-year-old male with tubular apocrine adenoma of the left upper eyelid, which recurred following initial incomplete excision. Although the lesion showed focal morphologic similarity to the apocrine variant of pleomorphic adenoma (chondroid syringoma), the diagnosis of tubular apocrine adenoma was supported by fluorescence in situ hybridization studies, which demonstrated absence of PLAG1 and HMGA2 gene rearrangements seen in pleomorphic adenoma. This case illustrates the clinical, microscopic and immunohistochemical features of tubular apocrine adenoma. The recent advances in our understanding of the molecular genetics of tubular apocrine adenoma and related tumors, and how these advances shape the evolving classification of sweat gland tumors are reviewed.