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

Inhibin B Secreting Ovarian Fibroma

Background

Nearly 90% of all the hormone-producing ovarian tumours are sex cord-stromal tumours (SCSTs). The Ovarian fibroma is a hormonally inactive variant of SCST. It is composed of spindle, oval, round cells producing collagen and accounts for approximately 4% of all ovarian neoplasms. Amongst the other SCSTs, Inhibin B is an important tumour marker. It is a heterodimeric glycoprotein hormone that is secreted primarily by the granulosa cells of the developing follicles. High levels of Inhibin-B can hamper follicular recruitment, leading to amenorrhea in a reproductive age woman.

Finding

In this case report, we describe a rare case of a reproductive age female presenting with secondary amenorrhea, having an Ovarian Fibroma, producing massive amounts of Inhibin B.

Significance

Although some pathological variants of ovarian fibromas like cyst-adeno-fibroma and ovarian fibro-thecoma are known to secrete inhibin B, benign /pure ovarian fibromas rarely do so.

Benign ovarian thecoma with markedly elevated serum inhibin B levels mimicking adult granulosa cell tumor

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A rare case of markedly elevated inhibin B associated with an ovarian thecoma.

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Inhibin B lacks specificity as a tumor marker for adult granulosa cell tumor.

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A full differential for elevated Inhibin B is important for improved preoperative counseling.

Introduction

Elevated serum inhibin B is a classic marker of adult granulosa cell tumors. Here we discuss an extremely rare and informative case of elevated inhibin B associated with an ovarian thecoma.

Case

A 57 year-old postmenopausal female presented with recurrent bleeding and was found to have an adnexal mass with an elevated serum inhibin B level of 1,915 pg/mL (normal range 10–200 pg/mL). With a preoperative diagnosis of adult granulosa cell tumor, she underwent surgical management for what was ultimately a benign ovarian thecoma. The diagnosis of thecoma was confirmed by a pericellular pattern of reticulin staining and the lack of a FOXL2 mutation by molecular testing.

Conclusion

This case demonstrates that inhibin B lacks specificity as a tumor marker for adult granulosa cell tumor, even at very high levels. Knowledge of benign alternative explanations for this finding can facilitate improved preoperative patient counseling. Pertinent literature is reviewed, with an emphasis on proposed hypotheses for inhibin overproduction.

The Effects of Inhibin B in the Chemotherapy Drug-Induced Premature Ovarian Insufficiency Mice and hPMSCs Treatment

Human placenta mesenchymal stem cells (hPMSCs), have been extensively investigated on the treatment of many diseases. This study was to explore the effects of hPMSCs treatment on the chemotherapy drug-induced premature ovarian insufficiency (POI) mice. Cyclophosphamide (120 mg/kg) and busulfan (30 mg/kg) or cyclophosphamide (70 mg/kg) induced POI mice were used and hPMSCs were injected through tail vein. The hormone levels of serum, morphological changes, the expression and quantitative analysis of inhibin B (INHBB) and FSHR protein, and apoptosis of granulosa cells in ovary were detected. The granulosa cells (GCs) were detected from ovaries of mice and the different concentration of cyclophosphamide on GCs were detected by MTT assay. The apoptosis of GCs was detected by FITC Annexin V Apoptosis Detection Kit. The significant increase in FSH and decrease in E₂ and INHBB were observed. Expression of human nuclei was observed in the stroma of ovaries. INHBB and FSHR levels of ovaries were reduced in the POI mice. Following hPMSCs treatment, the amounts of INHBB and FSHR significantly increased close to normal levels. The granulosa cells apoptosis increased in the POI ovaries but decreased after hPMSCs treatment. Moreover, cyclophosphamide has no effect on the GCs and no statistic difference was measured in vitro. The effects of hPMSCs treatment reduce the apoptosis of granulosa cells and restore the ovarian reserve capacity in chemotherapeutic drug-induced POI mice. The data help to further explore new potential clinical therapeutic approach for POI patients.