This article is more than 5 years old. Information may no longer be current.
When the lab values don’t make sense, keep looking
Click Here to Manage Email Alerts
A 49-year-old man presented for further evaluation and management of his hypogonadism. He had been seen by an endocrinologist in late 2001 when he presented with depression and wondered whether it might be the result of a “hormone problem.” After a careful, well-documented history and physical the only endocrine abnormality was that the testes were small and soft.
The patient had known about this for a while but was not troubled by it. Testing revealed a low normal total and free testosterone, normal prolactin, normal luteinizing hormone and an elevated follicle-stimulating hormone. Since then he has been treated with either transdermal or intra-muscular testosterone with no benefit that the patient could report. He remained depressed, had been on a number of anti-depressant medications, and was engaged in counseling with a psychiatrist.
My history and physical exam added nothing to what was already known. The karyotype was 46XY. Total T (off replacement therapy for several months) was 479 (reference interval 241- 827), free T was 71 (62-512), LH 33.5 (1.2 – 8.6), FSH 106 (1.3 – 19.3). Thyroid studies and prolactin were normal as were the biochemical and hematologic profiles. I checked with the lab to make sure that interfering substances did not affect the labs and had the studies validated with a second blood draw.
It was time to call my friends for advice and one knew this syndrome immediately as the Sertoli cell only syndrome — small soft testes containing cells but not tubules (in contrast to Klinefelter’s where the testes are small but firm because there are tubules present but not cells). The more usual presentation is with infertility, and the diagnosis is suggested by the examination of the testes and confirmed, if necessary, by testicular biopsy. In the absence of a biopsy that I can’t justify in my patient, serum Inhibin B (which is a testicular hormone with negative feedback on FSH) should be low.
Should I re-start testosterone therapy which has not helped him in the past? I will be guided by his wishes once we more fully discuss what has been found.