Elevated secretion of androstenedione in a patient with a Leydig cell tumour

In this study, we report the case of a 48-year old man with a well-encapsulated Leydig cell tumour, azoospermia, decreased libido and impotence. The basal peripheral blood levels of testosterone, dihydrotestosterone, 5 alpha-androstane-3 alpha,17 beta-diol and oestradiol were normal and oestrone was moderately increased. In contrast, androstenedione was extremely elevated at 521 ng/dl (normal: 88 +/- 60 ng/dl). Upon hCG stimulation, plasma testosterone increased 2.1-fold while androstenedione increased 1.4-fold. Plasma LH and FSH were also elevated and their response to LRH was exaggerated. At the time of surgery the levels of androstenedione in the spermatic vein plasma, as well as in the testicular tumour were elevated. In contrast, testosterone levels in the spermatic vein blood were decreased indicating a partial deficiency of 17 beta-hydroxysteroid dehydrogenase in the tumoural tissue. A follow-up study revealed that the contralateral testis did not respond to hCG although the sex steroid concentrations in the peripheral plasma were within normal limits. Plasma gonadotrophins remained elevated. These results demonstrate that this Leydig cell tumour secreted high amounts of androstenedione into the blood and that the contralateral testis exhibited an impaired androgenic function.