Hormonal profile of Leydig cell tumors with gynecomastia

The hormonal profile of estrogen-secreting Leydig cell tumors was studied in four patients. Plasma testosterone (T) and estradiol (E2) levels varied from day-to-day whereas the T/E2 ratios were decreased (22:85, normal 170 to 440). hCG administration induced a higher estrogen response in the patients than in normal men. The finding in the spermatic venous blood of the tumor-bearing testis of a particular biochemical profile, including a low T/E2 ratio (12:27), associated with high progesterone/17-hydroxyprogesterone ratios (0.13:0.26) and high 17-hydroxyprogesterone-androstenedione ratios (26:44), allowed localization of a small testicular tumor when no testicular abnormality was found clinically. Also, the E2 level was moderately elevated in the spermatic vein of one patient compared with normal men. Spermatic venous blood also was obtained after hCG administration in two patients. Increased estrogen and reduced T responses were found in the tumoral testis in comparison with the contralateral testis. In conclusion, the hormone content of spermatic venous effluent from testes containing an interstitial cell tumor is abnormal in several respects and such abnormalities allow detection of the tumor when it is not recognizable clinically.