Clinically it is impossible to make difference between the vulvar melanosis the harmless brown spotty change of the vulva and melanoma malignum, that is one of the most dangerous malignancies. Even the dermatoscopical examination was not efficient to exclude the melanoma surely. A small, representative biopsy was enough for the diagnosis, which has exempted the patient from the unjustified mutilating resections. On the patient's skin they detected also a few relatively small disseminated hypopigmented spots. Electronmicroscopically they could observe plenty of melanosomes and big melanosoma-complexes in the lower keratinocyte layers of the vulvar melanotic macules. Melanocytes could not be recognised in the hypopigmented spots.