Squamoid eccrine ductal carcinoma of the head and neck: Three consecutive cases highlighting aggressive behavior and diagnostic pitfalls

Abstract

Squamoid eccrine ductal carcinoma (SEDC) is a rare cutaneous adnexal malignancy that closely mimics conventional squamous cell carcinoma (SCC), particularly in superficial biopsy specimens. We report three consecutive patients with SEDC of the head and neck treated at a tertiary referral hospital over a 5-year period. All tumors were initially misdiagnosed as SCC and showed biphasic squamous and ductal differentiation with extensive perineural invasion. Achieving local control was challenging, and two patients developed locoregional recurrence. These cases highlight the diagnostic pitfall of SEDC, the importance of deep biopsy, and the need for complete excision, multidisciplinary management, and prolonged follow-up.