Inhibin A and inhibin B producing ovarian fibrothecoma revealed by suppression of follicle stimulating hormone (FSH) in a post-menopausal woman: report of the first case

Abstract

In this report, we describe the first case ever reported in the literature, of an inhibin-A (INHA) and inhibin-B (INHB) producing fibrothecoma. A post-menopausal woman was referred to our unit because of follicle stimulating hormone (FSH) level below the reference interval for postmenopausal women. By contrast luteinizing hormone, hCG, and estradiol levels were within normal range. This discrepancy suggested the secretion of FSH inhibitory factors. INHB and INHA levels were markedly elevated for age, 475 pg/mL and 100 pg/mL, respectively. Ultrasonography and MRI showed a pelvic mass of indeterminate nature. Abnormal inhibin secretion is generally observed in granulosa cell tumors. In this case this etiology was unlikely because of low estradiol and AMH levels. Surgical exploration revealed a 10 cm mass of the left ovary proven histologically to be an ovarian fibrothecoma (OFT). After tumor removal, INHB and INHA levels decreased rapidly. Only three cases of OFT with an important secretion of INHB have been reported to date. INHA secretion has never been associated with OFT. There is a need to develop coupled hormone and imaging strategies to diagnose the source of INH secretion in case of FSH/LH discrepancy.

Chinese abstract

此报道首次在文献中描述卵巢纤维卵泡膜细胞瘤中产生抑制素A(INHA)和抑制素B(INHB)。一位绝后妇女因卵泡刺激素 (FSH) 水平低于绝经妇女FSH水平参考区间转诊至我院, 该患者促黄体生成素、绒毛膜促性腺激素和雌二醇水平在正常范围。这种差异表明FSH分泌抑制因子。INHB和INHA明显高于该年龄段水平, 分别为475pg/ml和100pg/ml。超声和MRI显示盆腔包块, 性质未定。通常在颗粒细胞肿瘤中可见抑制素异常分泌, 但因为该患者体内较低的雌二醇和抗苗勒管激素水平, 患颗粒细胞瘤的可能性不大。剖腹探查显示左卵巢10cm肿物, 病理证实卵巢纤维卵泡膜细胞瘤(OFT)。肿瘤切除后, INHB和INHA水平迅速下降。迄今为止只报道了3例OFT分泌INHB, 而INHA分泌从未与OFT相关。在FSH/LH存在差异的情况下有必要开发偶联激素和影像学技术来帮助诊断INH的分泌来源。

Keywords:

• Fibrothecoma
• gonadotropins
• inhibin B
• inhibin A
• ovary

Declaration of interest

The authors declare that there are no conflicts of interest.

The study was supported in part by Institut de Recherche Endocrinienne et Métabolique, Paris.