Histopathological Examination of Hair Matrix Cysts

Hair matrix cysts (HMCs) were identified as rare hybrid cysts combining features of pilomatricoma and epidermal cysts, typically presenting as dark-red, dome-shaped nodules in children and adolescents. Histologically, HMCs exhibited a cyst wall with basaloid, transitional, and shadow cells, surrounded by a fibrous capsule with inflammatory cells. Key pathological features included basal-like cell layers, small cystic spaces, amorphous keratins, granulomatous reactions upon rupture, and beta-catenin accumulation indicating Wnt pathway activation. Differential diagnosis required histopathologic examination to distinguish HMCs from other cutaneous adnexal neoplasms. Treatment involved surgical resection and follow-up.