Ovarian dysgerminoma is a common malignant tumor that comprises of ovarian germ cells. It is a disease of adolescents and young women. It is diagnosed by physical examination and imaging methods and is treated by salpingo-oophorectomy, radiation, and chemotherapy.
Based on their origin, ovarian tumors can be classified into three groups. Epithelial tumors, at about 60% of all tumors but making up 85% of the malignant ones, constitute the largest group; germ cell tumors (second group) and sex cord-stromal tumors (third group), together with metastatic tumors, make up the remainder [1] [2]. Dysgerminomas make up a third of malignant germ cell tumors, although they constitute only 2% of ovarian tumors [3]. Dysgerminomas correspond to the seminomas of the testis.
Dysgerminomas present with the general symptoms of adnexal tumors: tenderness and pain in the pelvic or lower abdominal area [1], feeling of fullness and early satiety, and urinary problems. Abdominal enlargement can be the consequence of hemoperitoneum or the presence of a large mass [3].
Usually present unilaterally - with about 10-20% being bilateral- and present as firm masses. These are fast growing tumors, although with excellent prognosis [3] [4].
Dysgerminoma mainly occurs in young women; those with abnormal gonads, for example with Swyer syndrome (XY gonadal dysgenesis), have an increased risk of developing dysgerminomas.
It is composed of undifferentiated germ cells, with occasional granulomas and lymphocytes being present. About five percent have syncytiotrophoblastic giant cells present, which secrete lactate dehydrogenase, alkaline phosphatase [3], and human chorionic gonadotropin (HCG) [2]. Thus, in these cases, serum HCG may be elevated, but otherwise hormonal problems are not characteristic of dysgerminomas [4].
If a pelvic mass is detected, tests for pregnancy and sexually transmitted diseases, as background information, should be obtained in reproductive age women. Determination of lactate dehydrogenase and HCG levels may help in the diagnosis in cases where these are elevated.
The most important feature to determine is whether or not the tumor is malignant. After the physical characterization of the mass, the initial imaging method is a transvaginal ultrasound. Four sonographic features that distinguish between benign and malignant pelvic masses have been proposed [5], according to which malignancy is suggested by solid material in the tumor, the presence and location of flow on color doppler imaging, free intraperitoneal fluid, and thick septations within the tumor. The most significant association with malignancy was found in cases where a solid component was present; masses that had no solid component, or had strongly hyperechoic solid parts, were almost invariably benign [5]. Necrosis inside the solid mass was also an indicator of the malignant condition [1]. Another study found papillary projections, the most reliable predictor [6].
Most authors agree that no single sonographic feature has a strong enough diagnostic value for malignancy, and a number of scoring systems have been proposed to predict disease based on morphological features [6]. Technical improvements, such as 3-dimensional ultrasonography, which help in characterizing both the internal structure of the adnexal masses as well as their vascularization, lead to better judgment [7] [8]. Combining imaging results obtained with different sonographic systems for both morphology and vascularity of the masses also increases the accuracy of diagnosis [6].
Magnetic resonance imaging performs better than either ultrasonography or computed tomography in diagnosing malignant features in ovarian tumors (although not in extraovarian pelvic masses). However, ultrasonography detected abdominal spread with higher specificity than the other two imaging methods in few cases [9].
Surgery is not just a treatment, but also an important tool for characterizing the tumor and establishing the spread of the disease, and so contributes diagnostic information for follow-up therapy [3].