[Regional lymph node micrometastases in malignant melanoma of the skin].

Histological studies were conducted into 352 primary malignant melanomas of the skin together with 4,003 associated and surgically removed lymph nodes at the Institute of Pathology and Bacteriology of Kaiserin-Elisabeth-Spital, between 1982 and 1987. Particular attention was given to micrometastases of regional lymph nodes. 27 lymph node micrometastases were recorded from 25 patients. Spots of melanin were also found in lymphatic tissue, but no tumour cells were detectable. There is no clinical aid by which micrometastases of lymph nodes might be possibly diagnosed, and, on principle, they are greatly accidental findings even for the pathohistologist. However, undetected lymph node micrometastases may have a deteriorating impact upon the prognosis of malignant melanoma. Complete microscopic elucidation of surgically removed lymph nodes, there fore, is absolutely essential. Capillaries are present in abundance deep inside lymph nodes, and from these points of departure tumour cells may enter into the blood flow and cause haematogenic metastases. That is why the prognostic importance attributed to histologically verified micrometastases is just as great as that attached to macrometastases.