Squamoid Eccrine Ductal Carcinoma of the Eyelid: Clinicopathologic Correlation of a Case.

Squamoid eccrine ductal carcinoma (SEDC) is a rare cutaneous neoplasm that often manifests as a plaque or nodule in sun-exposed areas of older patients. Herein, the authors report the first case of SEDC in the eyelid. A 76-year-old man presented with a 2.5 × 1.5 mm area of left upper eyelid erythema, thickening, ulceration, and scaling with madarosis superotemporally just above the lash line. Full-thickness wedge biopsy demonstrated irregular epithelial tubules with nuclear atypia and focal squamous differentiation, consistent with SEDC. The patient underwent Mohs resection and has had no recurrence approximately 27 months after surgical removal. The authors present this case to raise awareness of SEDC to ophthalmologists as all previous cases have been described in the nonophthalmic literature. A full-thickness biopsy is recommended to avoid misdiagnosing SEDC as squamous cell carcinoma (SCC), a less aggressive tumor. With greater awareness, there may be increased recognition of this likely underreported, more malignant entity.