Endocrine investigations in two cases of feminizing Leydig cell tumour.

Two patients, aged 32 and 35 years, presented with gynaecomastia and a unilateral testicular tumour which proved to be a Leydig cell tumour. Pre-operative samples taken at 08.00 h on different days showed marked elevation of plasma oestradiol in the first patient, and very slight irregular oestradiol elevation in the second, plasma oestrone within the normal range in both patients, reduced plasma testosterone in the first patient and reduced or normal testosterone in the second, and low or low-normal serum LH and FSH in both patients. One of the patients received an oral dose of 100 mg of clomiphene citrate for 3 consecutive days which induced a rise in LH and FSH and a decrease in the 17-hydroxyprogesterone/androstenedione ratio. These data suggest the inhibiting effect of endogenous hyperoestrogenism on testicular steroidogenesis owing to both the reduction of gonadotropin secretion and a direct local negative effect on C 17,20-lyase. After human chorionic gonadotropin stimulation, oestradiol response was increased and abnormally prolonged, a finding which may be helpful when diagnosing a feminizing Leydig cell tumour; testosterone reached normal values. After removal of the tumoural testis, gynaecomastia regressed within a few days, gonadotropins increased, oestrogens dropped, testosterone and 5 alpha-dihydrotestosterone normalized in one patient but remained low in the other at day 30. The Leydig cells outside the tumour appeared morphologically normal, but the count gave evidence of juxtatumoural Leydig cell hyperplasia in areas where the tumour was well encapsulated while showing a significant reduction at a distance from the tumour and in the contralateral testis by comparison with control testes.(ABSTRACT TRUNCATED AT 250 WORDS)