In recent decades, there has been a steady increase in the incidence of skin cancer worldwide. Annual growth is from 3 to 10%. In the structure of the oncological morbidity of the population of the Russian Federation in 2016, malignant skin neoplasms (MSN), with the exception of melanoma, took the second ranking place, making up 11.7% (74 551 patients) among cancer patients. 81.3% of patients were diagnosed with the I stage of MSN, 15.8% — with stage II, in 1.9% — with stage III, 0.5% — with stage IV. Mortality in the first year since diagnosis was 0.6% in Russia and 1.6% in Moscow. Over the past decade, an increase in the incidence of skin cancer in Russia amounted to 26% (2007—2017). The risk group includes people with a light skin phenotype. In addition, skin cancer is more common in people who spend most of the time outdoors in direct sunlight. Despite the high prevalence of skin cancer and low mortality from it, there are conditions that are much more aggressive in the clinical course and are less treatable with standard methods — so-called rare (orphan) skin tumors. This article discusses these forms, describes the classification, etiology, risk factors, diagnostic and treatment methods for the possibility of rational prognosis and modern treatment of patients.