Acanthosis nigrica maligna (syn.: malignant black hairy) is a rare skin disease caused by increased proliferation of benign dark-colored cell granules in the stratum corneum. In this case, an uneven thickening of the stratum corneum occurs. The disease is chronic and relapsing. As a rule, the reasons for its development are not clear. The most likely cause is metabolic or neuroendocrine disorders. The mutation of melanocortin-1-alpha receptor, which converts interleukin-2 into melanocyte-stimulating hormone, leads to the development of hyperpigmentation of many areas of the body and, in particular, the vestibule of the vulva, the area of the labia majora, the bottom of the saucer, the bottom of the scrotum, the buttock