Abstract

Syringoid Eccrine Carcinoma (SEC) is a rare malignant adnexal carcinoma that can invade skin tissue but does not metastasize with frequency. Here, we present a case of a 92 yo gentleman who presented to clinic with a growth involving his left elbow. A shave biopsy of the lesion revealed an infiltrative epithelial tumor comprised of small and irregular islands of mature appearing cells that focally exhibited squamous differentiation. Duct formation was seen within the epithelial islands. Areas resembling acrosyringium were also noted. Collectively, these histopathological features were thought to be representative of the highly infiltrative eccrine tumor, Syringoid Eccrine Carcinoma. The histologic differential included an infiltrative squamous cell carcinoma with eccrine differentiation. S100, AE1/AE3 cytokeratin did not demonstrate definitive evidence of perineural invasion. A re-excision to achieve complete removal was recommended. Primary eccrine carcinomas are rare and account for less than 0.01% of all skin cancers1. SEC is thought to present primarily on the head and neck region of the body though there are rare reports demonstrating presentation on the trunk and extremities. It is important for pathologists to recognize this rare entity and its unique clinical and histological presentation. Reference: Moy RL, Rivkin JE, Lee H, Brooks WS, Zitelli JA. Syringoid eccrine carcinoma. J Am Acad Dermatol. 1991 May;24(5 Pt 2):857-60. doi: 10.1016/0190-9622(91)70133-m. PMID: 2050853.

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