Histochemical findings in different types of malignant melanoma: biological and clinical significance.

By means of histochemical methods (gel-film incubation-media) superficial spreading melanoma, nodular melanoma and lentigo maligna melanoma are investigated. The result of this examination is that with regard to their enzyme spectra, the nodular melanoma and the nodular part of the superficial spreading melanoma are very similar. Glucose-6-phosphate dehydrogenase shows the strongest enzyme reaction, followed by succinate dehydrogenase and lactate dehydrogenase. The beta-hydroxybutyrate dehydrogenase reaction is always weak. The reaction of acid phosphatase is between negative and weakly positive. Significant differences, however, are observed in lentigo maligna and in lentigo maligna melanoma. In both, the strongest formazan deposits are seen with succinate dehydrogenase, sometimes also with lactate dehydrogenase. The glucose-6-phosphate dehydrogenase reaction, however, is sometimes considerably weaker. In the case of lentigo maligna melanoma, the activity of beta-hydroxybutyrate dehydrogenase often is increased, and acid phosphatase also shows higher reactions than in the other melanomas. These differences in the enzyme pattern correspond to the different biological behavior of the tumours. The enzymatical and biological characteristics of lentigo maligna melanoma possibly derive more from the characteristics of the tumour itself which are not dependent on the area.