Muzic, John G.

BACKGROUND The incidence of rare cutaneous malignancies is unknown. Current estimates of rare cutaneous malignancy incidences are based on broad epidemiologic data or single institution experiences, not population-based data. OBJECTIVE To determine the incidence of several rare nonmelanoma skin cancers. MATERIALS AND METHODS The authors conducted a retrospective chart review of a population-based cohort between the years 2000 and 2010. Residents of Olmsted County, Minnesota, who were diagnosed with a biopsy-proven nonmelanoma skin cancer—excluding basal cell carcinoma and squamous cell carcinoma—were included in this study. The primary outcome was tumor incidence. Additionally, the authors extracted patient demographics, tumor characteristics, treatment modalities, and outcomes. RESULTS The age-adjusted and sex-adjusted incidences per 100,000 persons of multiple rare cutaneous malignancies were: atypical fibroxanthoma (1.8), sebaceous carcinoma (0.8), dermatofibrosarcoma protuberans (0.4), microcystic adnexal carcinoma (0.7), eccrine carcinoma (0.4), eccrine porocarcinoma (0.2), and leiomyosarcoma (0.2). CONCLUSION The authors report population-based incidences and clinical characteristics for these rare cutaneous malignancies. The immune status and smoking status of patients and the treatment and outcomes of these tumors are reported. Additional studies in a broader population are needed to further define the epidemiology and outcomes of these malignancies.