[Diffuse melanosis in malignant melanoma]

A patient with widely metastasized malignant melanoma assocaited with diffuse melanosis is presented. The widespread metastases in liver; skin and tonsilla are remarkable. The cutaneous melanosis in the form of the slate-blue colour caused by the increased dermal melanin deposits can arise in two different ways. One possibility is that melanin or precursors can be released from liver or other metastases and reach the dermis via the circulation. On the other hand a diffuse direct haematogenic single cell metastatic formation in the dermis with melanin formation and release can occur. In the case of the described patient the first etiopathology is dominating as it is shown by the light and electron microscopical results presented here.