[Malignant collision tumor of the skin : Melanoma, squamous cell carcinoma and basal cell carcinoma].

We present the case of a woman in her eighties with a collision tumor composed of a malignant melanoma, a squamous cell carcinoma and a basal cell carcinoma. The simultaneous growth of histogenetically different, spatially not separate, malignant tumors of the skin is rare. The classification is difficult and sometimes confusing, especially regarding the terminology used in the literature. The correct classification of such tumors has a high significance for the clinical daily routine.