Lymphocytic infiltration in uveal malignant melanoma

A study relating the intralesional infiltration of lymphocytes and plasma cells to patient survival was performed on cases of uveal malignant melanoma accessed at the Armed Forces Institute of Pathology, Washington, DC (AFIP) between 1954 and 1971. The authors examined 1193 cases using light microscopy. Of the 1078 cases with technically acceptable histologic sections, 134 tumors contained 100 or more lymphocytes per 20 high-power (X400) microscopic fields (20 HPF). The prevalence was 12.4%. This was designated the "high lymphocytic" group. An equivalent number of cases with fewer lymphocytes comprised the "low lymphocytic" group. The survival rate at 15 years was 36.7% for patients in the high lymphocytic group and 69.6% for patients in the low lymphocytic group. Using the Cox model, the authors found that an increased number of lymphocytes per 20 HPF was significantly associated with decreased survival (chi-square = 21.2, P = less than 0.0001). A significant association was observed even when we controlled for other risk factors (chi-square = 6.98, P = 0.008).