Endocrine Abstracts

Introduction: Gonadotroph adenomas usually present as clinically non-functioning sellar masses. They are extremely infrequent in children. Only some case report of children and adolescents with clinical manifestations of high serum gonadotrophin levels have been published. As in adult patients most of the gonadotroph adenomas have a silent growth, and therefore a late presentation as macroadenoma with mass effects.

Case report: This 16-year-old girl presented with menorrhagia, polymenorrhea and galactorrhea. Menarche had occured at 11 years of age and initially menses were regular. 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 2.6 cm). 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 3 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 26 mm adenoma.