Macrophages lysing seminoma cells in patients with carcinoma-in-situ (CIS) of the testis.

Testicles of 15 subfertile men who underwent orchidectomy because of intratubular seminoma cells resp. carcinoma-in-situ (CSI) pattern in testicular biopsy were examined by semithin sections as well as by ultrathin sections. With one exception the volume of the testicles was reduced (means = 16 ml). 6 cases (= 40%) had exclusively intratubular seminoma cells, 4 cases (= 26.6%) intratubular and interstitial seminoma cells and 5 cases (= 33.3%) a solid seminoma near the rete testis. In all patients an interstitial inflammatory infiltration as well as tubular shadows of various degree could be observed. Some tubular shadows contained macrophages in the center heavily loaded with lipid droplets. Furthermore, in two cases many seminiferous tubules could be detected which contained activated macrophages in the lumen lysing tumor cells. One of the patients had only intratubular tumor cells, whereas the other patient had a solid seminoma near the rete testis. Our data suggest that activated macrophages killing intratubular tumor cells in patients with CIS pattern of the testis resp. with an early stage of a seminoma represent a physiological immunological reaction of the host in preventing further invasive tumor growth. Tubular shadows represent the final process of macrophage activity and may explain the reduced testicular volume in patients with CIS. However, the density of the inflammatory reaction and the extent of intratubular macrophages lysing tumor cells does not correlate with a low or high risk of tumor growth.