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Case Reports

Abstract

Recently, we saw a 56 yo male who presented with a cm tumor of the right cheek. Sections revealed acanthosis, papillomatosis, and a dermal epithelial proliferation with a basal budding nodule composed of closely arranged oncocytes with large, uniform, oval to polygonal cells with intensely eosinophilic cytoplasm and enlarged nucleoli that formed ducts. Oncocytes extended into the epidermis, with small infiltrative dermal nests eliciting stromal fibrosis. A central cystic structure was lined by cells with apocrine features and mucinous vacuolar cytoplasm, confirmed mucicarmine-positive. No severe atypia, necrosis, or high mitotic activity was identified. 

Review of prior literature revealed only two reported cases, both lacking mucinous metaplasia, infiltrative features, or epidermal attachment like our case. This represents the third reported case of cutaneous oncocytic hidradenoma, and the first with combined mucinous metaplasia, focal infiltration, and epidermal attachment. Recognition of these features is important to avoid misdiagnosis as other oncocytic neoplasms, including apocrine adenomas, poroid tumors, granular cell tumors, PEComa, and metastases.