Bilateral ovarian fibrothecoma. An uncommon cause of a large pelvic mass

A typical case of ovarian fibrothecoma in a paucisymptomatic postmenopausal woman

Ovarian fibrothecomas are a rare type of gonadal stromal cell tumor. They are mostly benign and unilateral in 90% of cases and mainly affect postmenopausal women. The clinical presentation and radiological features are vague. As a result, they may be misdiagnosed or confused with other entities. The definitive diagnosis is made by histology. We present a case of ovarian fibrothecoma in a 65-year-old woman with a history of thyroid neoplasia who presented only with frustrating abdominal pain with no other associated signs.

Fibrothecoma of the Ovary; Clinical and Imaging Characteristics

Introduction

Ovarian fibrothecoma is a rare benign sex cord-stromal ovarian tumor sorted under the thecoma-fibroma group. We present an analysis of clinical and laboratory findings and the radiological characteristic features of pathologically proven fibrothecomas in variable imaging modalities.

Methods

A retrospective analysis was done for 88 patients with 90 pathologically proven ovarian fibrothecoma between January 2011 and December 2023 from our center's prospectively maintained database. All the patients underwent preoperative ultrasonography, computed tomography (CT), and magnetic resonance imaging (MRI) scans, clinical examinations, basic laboratory tests, and tumor markers.

Results

The results of Spearman's correlation revealed a statistically significant positive correlation between the largest tumor diameter and serum level. CA 125, the degree of ascites, and diffusion weighted imaging (DWI) signal intensity while the results of point biserial correlation revealed a statistically significant correlation of the largest tumor diameter with the presence of ascites, cystic changes, abdominal enlargement, surgery type, and border type. There were also statistically significantly higher hypoechoic lesions in the smaller tumor group (p = 0.001) but not for isoechoic (p = 0.099) and mixed (p = 0.052). Regarding the MRI, there was a statistically significantly larger tumor diameter in T2 mixed-hyperintense versus hypointense (p = 0.007) and intermediate (p = 0.010) signal intensities.

Conclusion

Fibrothecoma showed a statistically significant positive correlation between the largest tumor diameter with serum level CA 125 and the amount of ascites. On imaging, it shows mild enhancement in both CT and MRI, with a statistically significant positive correlation of the largest tumor diameter with T2 and DWI signal intensity.

Imaging features of intra-abdominal and intra-pelvic causes of hirsutism

Hirsutism is a relatively common disorder which affects approximately 5% to 15% of women. It is defined by excessive growth of terminal hair in women, which primarily affects areas dependent on androgens, such as the face, abdomen, buttocks, and thighs. Hirsutism can be caused by a variety of etiologies, which are most often not lifethreatening. However, in some cases, hirsutism can be an indicator of more serious underlying pathology, such as a neoplasm, which may require further elucidation with imaging. Within the abdomen and pelvis, adrenal and ovarian pathologies are the primary consideration. The goal of this manuscript is to review the etiologies and imaging features of various intra-abdominal and intra-pelvic causes of hirsutism.

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

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.

Hypoxia is important in F‑18 FDG accumulation in thecoma‑fibroma tumors on F‑18 FDG PET/CT scans

Several studies have noted benign thecoma-fibroma tumors with positive F-18 fluorodeoxyglucose (FDG) accumulation mimicking malignant ovarian tumors following F-18 FDG positron emission tomography (PET). The present study analyzed four cases with false-positive F-18 FDG PET/computed tomography (CT) diagnoses of thecoma-fibroma tumors as malignant tumors due to F-18 FDG accumulation, compared with eight cases of FDG-positive ovarian cancers and two cases of FDG-negative fibromas. Hypoxia inducible factor (HIF)-1α expression was examined in the six thecoma-fibroma tumors using reverse transcription-polymerase chain reaction (RT-PCR). The four F-18 FDG-positive cases exhibited higher cellularity, maximum standard uptake and signal intensity on T2-weighted imaging, and gadolinium (Gd) enhancement using magnetic resonance imaging than the two FDG-negative fibroma cases. In the F-18 FDG-positive thecoma-fibroma group, Ki-67 expression was low and LAT1 expression was not identified, ruling out the diagnosis and potential for malignancy. However, considerable glucose transporter 1, HIF-1α, and vascular endothelial growth factor expression was observed. HIF-1α expression was elevated in all four false-positive cases by RT-PCR. From these results, it was hypothesized that hypoxia due to elevated cellularity may stimulate HIF-1α expression and be associated with F-18 FDG accumulation in F-18-positive thecoma-fibroma tumors.