Human Reproduction, Vol. 18, No. 3, 502-505,
March 2003
© 2003 European Society of Human Reproduction and Embryology
Pseudo-isolated FSH deficiency caused by an inhibin B-secreting granulosa cell tumour: Case report
1 Pediatric & Reproductive Endocrinology Branch, National Institutes of Health, Bethesda, MD 20892 and 2 Department of Obstetrics and Gynecology, Uniformed Services University of the Health Sciences, Bethesda, MD 20814, USA
3 To whom correspondence should be addressed at: NICHD, Pediatric & Reproductive Endocrinology Branch, Building 10, Room 9D-42, Bethesda, MD 20892, USA. e-mail: segarsj{at}mail.nih.gov
Isolated FSH deficiency due to a mutation in the FSH
subunit is characterized by an extremely low serum FSH concentration. We report a patient who presented with an FSH of 0.8 mIU/ml and infertility associated with anovulation. Endocrinological assessment and immunohistochemistry revealed that a granulosa cell tumour was secreting inhibin B and suppressing FSH; however, LH and estradiol were within their normal ranges. Upon removal of the tumour, inhibin B decreased and FSH levels rose to normal values. The patient subsequently conceived and delivered successfully. Based on this case and on those previously described in the literature, we suggest that inhibin B levels should be evaluated in anovulatory patients having a clinical presentation consistent with functional hypothalamic amenorrhoea and very low to normal values of FSH.
Key words: FSH deficiency/granulosa cell tumour/hypothalamic amenorrhoea/infertility/inhibin B