Pure dysgerminoma of the ovary: CT and MRI features with pathological correlation in 13 tumors

Abstract

Background: To investigate the spectrum of CT and MRI findings of dysgerminoma of the ovary. Methods: CT and MRI imaging of 12 patients with 13 histologically proven dysgerminomas of the ovary were retrospectively reviewed. Patients , ages ranged from 6~27 years (mean, 17.2 years). Two observers evaluated the following CT and MRI features of the tumor by consensus: (i) location, shape, and size; (ii) attenuation, T2 signal intensity, and ADC value; (iii) patterns of contrast enhancement; (iv) presence of fibrovascular septa; (v) presence of necrosis, hemorrhage, and calcification; (vi) presence of "ovarian vascular pedicle" sign. We also noted the extent or stage of the tumors. Results: 75% lesions arised in the right ovary. Bilateral ovaries were involved in one case. Tumors displayed as a purely or predominantly solid mass (mean size, 17.0 ± 7.8 cm). Ten tumors were shaped multilobulated. The mean ADC value of lesions was 0.830 ± 0.154 × 10 − 3 mm 2 /s. Characteristic fibrovascular septa were observed in all lesions. Among them, classic septa were present in 69% lesions. They were thin, hypointense on T2WI with a linear intense enhancement indicating the blood vessels in septa. Due to the stromal edema, fibrovascular septa may become thick even amorphous in shape, hyperintense on T2WI and even low attenuation on CT with a slight enhancement except for a bright blood vessel on the edge. Massive necrosis was observed only in one lesion. Calcification was present in 3 of the 5 tumors on CT. "Ovarian vascular pedicle" sign was present in 12 lesions. Lymphadenopathy, retroperitoneal spread, and distant metastases combined with an implantation in Douglas' cul-de-sac were present in one patient respectively. Conclusion: On CT and MR images, ovarian dysgerminoma often appears as a large solid mass. The edematous condition of characteristic fibrovascular septa can be well displayed by imaging which then can guide the radiologists to make an accurate diagnosis. Calcifications often occur in the tumor. Nonspecific low ADC value and "ovarian vascular pedicle" sign may narrow the differential diagnosis.

Systematic review and meta-analysis of imaging differential diagnosis of benign and malignant ovarian tumors

“…Thus, MRI is better than CT in distinguishing between benign and malignant ovarian tumors. As CT scans only show the defect of the cross-sectional image, it is difficult to distinguish between endometriotic cysts, the uterine serosal layer or ovarian tumors (25,26). Conversely, MRI uses multi-directional and multi-level imaging, obtains a larger amount of information, a higher resolution of soft tissues, and clearly defines the range of edema, inflammation, tumors, etc., and thus provides certain biochemical and pathological information (21,24,26).…”

Paediatric Ovarian Dysgerminoma: A Case Report

“…The histogenesis of dysgerminoma may account for its preference for the right ovary, as differentiation of ovarian tissue on the right side occurs more slowly and to a lesser extent than on the left side. 8 The prognosis and clinical characteristics of the tumour depend on its stage. A five-year survival rate of more than 75% overall is satisfactory (even 90% in stage I), dropping to about 63% in patients with an illness that has spread beyond the ovaries.…”

“…In CT and MR imaging, it frequently appears as a large multilobulated purely or predominantly solid mass. 8 In young patients, the standard treatment for dysgerminoma is usually fertility-sparing surgery with unilateral salpingo-oophorectomy. 6 Preservation of the contralateral ovary leads to "recurrent" dysgerminoma in 5 to 10% of retained gonads during the next 2 years.…”

Ovarian dysgerminoma with pseudo-Meigs syndrome

“…[ 8 , 9 ] The presence of tumor nest multiplicity, central blood vessels and ovarian vascular pedicle on radiological images may aid in diagnosing dysgerminoma. [ 10 ] This tumor is the ovarian counterpart of testicular seminoma and is therefore histologically similar. About 80% to 90% dysgerminomas are unilateral and consist of undifferentiated germ cells and large vesicle cells scattered in the bed sheet or umbilical cord.…”