The risk of lymph node involvement in malignant cutaneous adnexal tumors

Malignant cutaneous adnexal tumors (MCATs) are rare neoplasms that do not have a well-studied treatment algorithm. They are generally treated by excision alone. Given its successful application in other cutaneous malignancies, sentinel lymph node biopsy (SLNB) has been advocated by some for use in MCATs. A retrospective chart review was performed. Clinicopathological factors, recurrence patterns, and long-term follow-up were documented. Survival analysis was performed. Forty-eight subjects were identified. Mean age was 69 years with locations on the face (52%), including periocular sites (16%), extremities (25%), and all other sites (7%). Histologic distribution was sebaceous carcinoma (56%), porocarcinoma (17%), eccrine carcinoma (13%), adenocarcinoma (10%), and hidradenocarcinoma (4%). Mean follow-up was 3.9 years (range, 0 to 17 years). Nine subjects (18.8%) recurred locally, and recurrence was inversely associated with age (P = 0.04). Four (8.3%) demonstrated lymph node involvement, none without first developing local recurrence. Five-year disease-specific survival was 97 per cent (confidence interval, 81.4 to 99.6%). Despite being one of the largest reported analyses of MCATs, this study is limited by the small number of subjects. MCATs seemingly develop nodal recurrence only after demonstrating aggressive local biology. SLNB may best be applied selectively, possibly only in patients with local recurrence.