Surgery and Adjuvant Radiation for High-risk Skin Adnexal Carcinoma of the Head and Neck

Skin adnexal carcinoma (SAC) is a rare cutaneous malignancy that arises from sebaceous and sweat glands. These carcinomas are believed to behave more aggressively than cutaneous squamous cell carcinomas (SCC) with a propensity for local recurrence. The role of adjuvant radiotherapy in SAC is undefined. Methods: We retrospectively reviewed all cases of head and neck SAC treated with surgery and adjuvant radiation from 2000 to 2012 at a single institution. Results: Nine cases were identified. Median age was 67 (range, 52 to 88) years. The histologies were: Adnexal carcinoma (n=1), adnexal carcinoma with sebaceous differentiation (n=1), adnexal carcinoma with squamous differentiation (n=1), skin appendage carcinoma (n=1), sclerosing sweat duct carcinoma (n=1), mucinous carcinoma (n=1), ductal eccrine adenocarcinoma (n=1), porocarcinoma (n=1), and trichilemmal carcinoma (n=1). All tumors were reviewed by a dermatopathologist to confirm the SAC diagnosis. All patients had undergone surgery. Indications for adjuvant radiation included involved lymph nodes (n=4), perineural invasion (n=2), nodal extracapsular extension (n=2), positive margin (n=1), high-grade histology (n=6), multifocal disease (n=2), and/or recurrent disease (n=5). Radiation was delivered to the primary site alone (n=3), to the draining lymphatics alone (n=2), or to both (n=4). One patient received concurrent cisplatin. Median dose to the primary site was 60 Gy and to the neck was 50 Gy. Median follow-up was 4.0 years (range, 0.6 to 11.4 y). Locoregional control was 100%. Five-year progression-free survival was 89%. There was 1 acute grade 3 toxicity and no greater than or equal to grade 2 late toxicities were recorded. Conclusions: Surgery and adjuvant radiation for high-risk SAC offers excellent locoregional control with acceptable toxicity.