Ovarian Malignant Germ Cell Tumors: Cellular Classification and Clinical and Imaging Features

Abstract

Ovarian malignant germ cell tumors (OMGCTs) are heterogeneous tumors that are derived from the primitive germ cells of the embryonic gonad. OMGCTs are rare, accounting for about 2.6% of all ovarian malignancies, and typically manifest in adolescence, usually with abdominal pain, a palpable mass, and elevated serum tumor marker levels, which may serve as an adjunct in the initial diagnosis, monitoring during therapy, and posttreatment surveillance. Dysgerminoma, the most common malignant germ cell tumor, usually manifests as a solid mass. Immature teratomas manifest as a solid mass with scattered foci of fat and calcifications. Yolk sac tumors usually manifest as a mixed solid and cystic mass. Capsular rupture or the bright dot sign, a result of increased vascularity and the formation of small vascular aneurysms, may be present. Embryonal carcinomas and polyembryomas rarely manifest in a pure form and are more commonly part of a mixed germ cell tumor. Some OMGCTs have characteristic features that allow a diagnosis to be confidently made, whereas others have nonspecific features, which make them difficult to diagnose. However, imaging features, the patient's age at presentation, and tumor markers may help establish a reasonable differential diagnosis. Malignant ovarian germ cell tumors spread in the same manner as epithelial ovarian neoplasms but are more likely to involve regional lymph nodes. Preoperative imaging may depict local extension, peritoneal disease, and distant metastases. Suspicious areas may be sampled during surgery. Because OMGCTs are almost always unilateral and are chemosensitive, fertility-sparing surgery is the standard of care.

Fertility-sparing for young patients with gynecologic cancer: How MRI can guide patient selection prior to conservative management

“…Malignant germ cell tumors manifest in very young women (younger than 20 years) and are the most common ovarian malignancy in this age group (Figure 8, and Figure 9) (127). Dysgerminomas and immature teratomas are the most frequent, followed by yolk sac and mixed tumors (134). Most patients present with Stage I (ovary-confined) disease and have >90% 5-year overall survival; even advanced-stage disease has a good prognosis due to high chemosensitivity making fertility preservation possible (135).…”

“…Elevation of these markers can aid diagnosis; normal levels don’t rule out ovarian tumor. Elevated AFP or hCG are virtually diagnostic of malignant germ cell tumors (134). CA-125 can be raised with epithelial tumors (both borderline and invasive types), although non-neoplastic conditions including endometriosis, pelvic inflammatory disease, and uterine leiomyoma may also cause nonspecific elevation.…”

“…If fat is observed within adnexal mass (high SI on TWI that suppresses after fat saturation), the differential diagnosis is narrowed to frequent mature cystic teratoma or rare malignant immature teratoma. Mature teratoma often presents as a cystic mass filled with fatty sebaceous fluid and may contain coarse tooth-like calcifications (best seen on CT) allowing confident diagnosis of a benign mass (134). In contrast, immature teratoma is typically a solid-cystic mass with small foci of fat, cysts filled with simple fluid, and scattered fine calcifications (best seen on CT) (134).…”

CT imaging of ovarian yolk sac tumor with emphasis on differential diagnosis

“…Intralesional vessels of YSTs usually have dilated lumen and marked enhancement. This classical imaging finding is considered to be a result of increased vascularity and the formation of small vascular aneurysms in the tumor8.…”

ecancermedicalscience

“…The embryonal carcinoma and the polyembryoma rarely show in their pure form. Instead, they become a part of the mixed tumours of germ cells (see Table 2) [30]. …”