Low-Grade Trichoblastic Carcinoma of the Scalp: A Rare Case Managed With Adjuvant Radiotherapy

Trichoblastic carcinoma (TBC) is a rare malignant adnexal tumor originating from follicular germinative cells. It can resemble basal cell carcinoma (BCC) both clinically and histologically, often leading to diagnostic and therapeutic challenges. We report a 44-year-old male patient who presented with a recurrent exophytic scalp lesion initially diagnosed as pilomatrixoma. Following wide local excision, histopathologic analysis revealed a low-grade TBC with narrow margins. Due to the close proximity of tumor cells to the surgical margins, the patient underwent adjuvant volumetric modulated arc therapy (VMAT) to a total dose of 50 Gy in 20 fractions. This case underscores the importance of accurate histopathologic differentiation between TBC and BCC. Surgical excision with adequate margins remains the treatment of choice, while adjuvant radiotherapy may be warranted in cases with narrow or positive margins to prevent recurrence.