CASE 13585 Published on 26.04.2016

Granulosa cell tumor of the ovary: functional MRI

Section

Genital (female) imaging

Case Type

Clinical Cases

Authors

Athina C. Tsili, Christina Naka, Vasilios Maliakas, Maria I. Argyropoulou

Department of Clinical Radiology,
Medical School,
University of Ioannina,
45110, Ioannina, Greece; E
mail:a_tsili@yahoo.gr, atsili@cc.uoi.gr
Patient

38 years, female

Categories
Area of Interest Genital / Reproductive system female ; Imaging Technique MR, MR-Diffusion/Perfusion
Clinical History
A 38-year-old woman was referred for MRI of the pelvis due to infertility.
Imaging Findings
MRI examination revealed the presence of a mainly solid right ovarian mass
(Fig. 1-3), measuring 2.9 x 2.1 x 3.3 cm. The lesion was well-defined, mainly isointense on both T1 and T2-weighted images (Fig. 1), when compared to the normal myometrium. Dynamic contrast-enhanced images showed strong and heterogeneous mass enhancement, with an earlier and steeper rise than that of the normal myometrium and a curve type 3 (Fig. 2). Hyperintense areas on T2-weighted images, with absence of contrast enhancement, proved to represent internal cysts on pathology. Restricted diffusion was seen within the mass, which was detected mainly hyperintense and hypointense on DWI and ADC maps, respectively (Fig. 3). Neither peritoneal seeding nor pelvic lymphadenopathy was detected.
Discussion
Background
Histology following right salpingo-oophorectomy reported an early-stage (FIGO IA) granulosa cell tumour (GCT) of the ovary.
Ovarian GCT accounts for less than 5% of ovarian malignancies [1]. It represents the commonest malignant sex cord–stromal tumour and the most common oestrogen-producing ovarian neoplasm. Most patients have an excellent prognosis [1].
Imaging Perspective
GCTs of the ovary have variable histopathologic characteristics resulting in a spectrum of imaging findings [2-4]. They may have the appearance of solid masses, tumors with haemorrhagic or fibrotic changes, multilocular cystic lesions filled with watery fluid or haemorrhage, or completely cystic tumours [2-4]. Functional MRI techniques, including dynamic contrast-enhanced (DCE) MRI and diffusion-weighted imaging (DWI) have been reported to improve the diagnostic assessment of ovarian masses [5]. There is paucity in the English literature regarding the functional MRI characteristics of ovarian GCTs.
DCE-MRI might provide useful information in differentiating among benign, borderline, and invasive epithelial tumours [6-11]. Invasive ovarian tumours usually show early and strong enhancement, with an initial rise steeper than that of myometrium, defined as “curve type 3” [6-11]. A correlation between the early enhancement patterns of ovarian epithelial tumours and tumoral angiogenic status including pericyte coverage index and vascular endothelial growth factor receptor expression has been reported [8]. Quantitative DCE-MRI has been reported as useful in the differentiation between malignant and benign ovarian tumours, with malignancies displaying higher tissue blood flow, higher blood volume fraction, higher area under the enhancing curve and lower interstitial volume fraction compared to benign tumours [9].
ADC mapping is reported less useful in the characterization of ovarian masses because of the considerable overlap of mean and lowest ADC values [5, 11-16]. This mainly reflects the increased mean ADC detected in ovarian malignancies and the decreased lowest ADC in benign lesions. The presence of desmoplastic stroma and/or fluid between papillary projections may be the cause of increased mean ADC in malignant tumours. Bundles and storiform patterns of spindle cells in fibromas, thick proteinaceous or bloody products in endometriomas, keratinoid substance in mature cystic teratomas may cause decreased lowest ADC in benign ovarian lesions [11-16]. However, DWI signal intensity in combination with morphologic findings has been reported as an accurate tool for differentiating complex adnexal masses. Specifically, the presence of a solid component with intermediate T2 signal and high b 1, 000 signal intensity was associated with a positive likelihood-ratio of 4.5 for a malignant ovarian tumour [12].
Differential Diagnosis List
Granulosa cell tumour of the ovary
Serous cystadenocarcinoma
Endometrioid carcinoma
Malignant germ cell tumour
Final Diagnosis
Granulosa cell tumour of the ovary
Case information
URL: https://www.eurorad.org/case/13585
DOI: 10.1594/EURORAD/CASE.13585
ISSN: 1563-4086