Comparative histological studies of regional lymph nodes of 201 melanoma patients. (Microscopic features in relation to individual age, site, and metastatic spread).

Since May 1968 a total of 2.108 regional lymph nodes (l.n.) dissected from 201 melanoma patients (86 axillary, 107 groin, and 8 neck) have become available for study. The purpose was to detect histological differences between the l.n. of 134 patients lacking and those of 67 patients exhibiting l.n. metastases, histologically verified in 104 of 706 nodes. The main finding is a more than six-fold increase in number and an eleven-fold increase in total area (evaluated by a microscope micrometer) of germinal centers in the lymph follicles of patients with, as compared to those without, l.n. metastases (P less than or equal to 0.05). Paracortical areas were found to be diminished in 56.7% of cases with metastatic spread. Accumulations of plasma cells were mainly seen in the nodes of elderly patients (48.4%) and of those exhibiting regional metastases (47.8%). The observation of numerous and dilated blood vessels in the interfollicular regions noticeably corresponded to the occurrence of lymphatic metastases (P less than or equal to 0.01), suggesting a "tumor angiogenic factor". A negative correlation with metastatic involvement was found as to histiocytosis of marginal sinuses and with respect to the observed fibrinoid hyalinosis of pulp vessels (P less than or equal to 0.01). The marked hyperplasia of lymph node B-lymphocyte regions as opposed to diminished T-lymphocyte areas prevailing in cases with metastatic melanoma is in accord with findings of humoral immunologic blocking activity and impaired T-cell response in advanced malignant melanoma.