Follicle-Stimulating Hormone-Secreting Pituitary Macroadenoma - a rare cause of abnormal menstrual cycles in a teenage girl

Program: Abstracts - Orals, Featured Poster Presentations, and Posters
Session: SAT 164-196-Pituitary
Saturday, June 15, 2013: 1:45 PM-3:45 PM
Expo Halls ABC (Moscone Center)

Poster Board SAT-173
Birsen Arici*, Christopher Kelly, Henryk Zulewski and Luigi Mariani
University Hospital Basel, Basel, Switzerland
Introduction: Gonadotroph adenomas usually present as clinically non-functioning sellar masses. They are extremely infrequent in children. Only some case reports of children and adolescents with clinical manifestations of high serum gonadotrophin levels have been published.

Case report: This 16-year-old girl presented with menorrhagia, polymenorrhea and galactorrhea. The patient reported a high frequent and prolonged menstrual bleeding since one year. A gynaecological examination revealed multicystic right ovary without other pathological findings and a gestagen-only pill was prescribed. After starting this treatment an oligomenorrhea with menstrual bleeding every two month occurred. Nine month later the patient developed galactorrhea and prolactin was slightly elevated with 1117 mU/l (reference < 530 mU/l). With suspicious for prolactinoma a therapy with bromocriptin was initiated and a radiological evaluation revealed a pituitary macroadenoma (largest diameter 2.6cm). Although prolactin levels normalized the size of pituitary mass remained unchanged. Ophthalmologic evaluation showed bitemporal hemianopsia. Medication with Parlodel® and Cerazette® was stopped and she was referred to our institution for urgent transsphenoidal resection. Preoperative endocrine evaluation showed following laboratory parameters: LH < 0.1 IU/l (0.5-41.7), FSH 23 IU/l (1.6-17.0), estradiol 3679 pmol/l (46-1828), prolactin 2405 mU/l (78-492), IGF1 39.4 nmol/l (25.1-95.0), fT4 16.1 pmol/l (12.6-21.0), TSH 4.0 mIU/l (0.51-4.30) and cortisol 506 nmol/l (80-638). At this time she had on-going menstrual bleeding for the last three weeks and no current medication. Elevated estradiol and FSH and suppressed LH was compatible with FSH-secreting pituitary adenoma. The somatotroph, thyreotroph and corticotroph axes were preserved and no disturbance of the water balance was noted. Hyperprolactinemia was interpreted as consequence of high estradiol levels and pituitary stalk compression.The postoperative course was uneventful except for a possible rhinoliquorrhea which resolved after 3 days of lumbar CFS drainage. The histopathological evaluation confirmed the diagnosis of atypical pituitary adenoma and showed immunohistochemical positivity for FSH in numerous cells. One month later normal menstrual cycle resumed and endocrine tests showed normal laboratory parameters.

Conclusion: In this case of FSH-producing pituitary adenoma the medical history of on-going menstrual bleeding associated with highly increased estradiol, high FSH and suppressed LH were the diagnostic hallmarks. The presence of polycystic ovaries is also typical for this condition. The slightly elevated prolactin level was  initially misinterpreted as evidence for prolactinoma that would have presented with much higher values in a 26mm adenoma.

Nothing to Disclose: BA, CK, HZ, LM

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