[Halo Nevus (Morbus Sutton): model of an immunological tumor regression]

Spontaneous regressions of malignant tumors are rare in the history of malignant disease. In malignant melanoma immunological mechanisms were accounted for the regressions observed. By the clinical phenomenon called Halo nevus a benign pigment-cell-tumor is described which shows spontaneous involution. The characteristic feature is the depigmentation of the surrounding uninvolved skin and a centripetal progression of the tumor-regression-phenomenon. In the present study it is demonstrated by histopathological and immunological investigations that lymphocytes are responsible for this tumor-regression. Lymphocyte-reactivity of 16 patients with Sutton's disease in different stages were investigated in the microcytotoxicity-assay against culture-grown melanomatargetcells. In 11 patients a specific cell-mediated immunity against the melanoma cells could be demonstrated in vitro. 5 patients did not show any reactivity, the Halo nevus had been removed by surgery 2 years earlier. The results of the immunological assay are confirmed by histopathological light- and electron-microscopic incestigations and documented by typical examples.