Ovarian Dysgerminomas

Updated: Sep 23, 2019
  • Author: Chad M Michener, MD; Chief Editor: Warner K Huh, MD  more...
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Overview

Background

The three major types of ovarian tumors are epithelial, sex cord, and germ cell. Epithelial cell tumors represent the majority of all ovarian neoplasms (82%). Conversely, germ cell tumors (GCTs) are rare, comprising approximately 20% of all ovarian tumors, both benign and malignant. Approximately 3-5% of ovarian GCTs are malignant. The most commonly occurring GCT is the dysgerminoma, which accounts for approximately 2% of all ovarian cancers.

Although rare, dysgerminomas are important irrespective of incidence because they most commonly affect women of reproductive age (ie, < 30 y). In fact, dysgerminomas make up two thirds of all malignant ovarian neoplasms in women younger than 20 years. Moreover, once diagnosed, dysgerminomas respond well to therapy, potentially sparing patients from infertility and early mortality.

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Pathophysiology

Typically, germ cells are encapsulated at birth within the primordial follicle. If they somehow escape encapsulation, cell death usually occurs. If the germ cells survive, rapid growth ensues, owing to the lack of normal contact inhibition, hence germ cell tumor (GCT) formation. All dysgerminomas are considered malignant, but only one third of dysgerminomas behave aggressively. The exact etiology of dysgerminomas has not been determined, although recent molecular studies have implicated loss of function with potential tumor suppressor gene TRC8/RNF139 as a possible etiology. [1]

Additionally, 5% of all dysgerminomas occur in dysgenetic gonads and may be associated with gonadoblastomas. Genetic disorders of the ovary are associated with karyotypic abnormalities and are discussed in Dysgerminomas in patients with karyotypic abnormalities in Complications.

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Etiology

The exact etiology for this tumor type has not been elucidated.

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Epidemiology

Frequency

The US incidence of dysgerminomas has remained unchanged over the last 30 years. The frequencies of the most common malignant ovarian neoplasms in women of reproductive age are as follows: epithelial tumors (42%); dysgerminoma and other germ cell tumors (GCTs) (30%); metastatic Krukenberg tumors (14%); and sex cord stromal tumors (ie, Sertoli-Leydig cell tumors) (13%).

Race

To date, no racial predilection exists for ovarian germ cell tumors (GCTs).

Sex

These tumors mostly occur in women, although the disease also occurs in pseudohermaphrodites and patients with gonadal dysgenesis (see Complications). Testicular seminomas are the male histologic counterparts to dysgerminomas.

Age

Although most ovarian cancers occur during the menopausal and perimenopausal years (ie, 50-59 y), dysgerminomas tend to occur frequently in the pediatric population. Dysgerminomas are most commonly observed in younger women. Seventy-five percent of dysgerminomas occur in patients in the third and fourth decades of life, with the mean age being 22 years.

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Prognosis

The 5-year survival rate is 96% if the tumor is confined to the ovary and 63% if extension occurs beyond the ovaries. Pregnancy does not alter the prognosis of most ovarian malignancies, but complications such as torsion and rupture may increase the incidence of spontaneous abortion or preterm delivery.

Prognosis depends on the staging of the tumors.

Five-year survival rates are as follows:

  • Stage Ia-Ic - 91%
  • Stage III - 74%
  • Stage III with retroperitoneal disease - 24%

Ten-year survival rates, comparing conservative surgery alone versus surgery plus radiation, are 92% and 85%, respectively.

As a rule, any peritoneal involvement carries a poor prognosis. No correlation exists between tumor size and prognosis.

In a 2014 retrospective review (1978-2010) of data from the Surveillance, Epidemiology and End Results program that evaluated cause-specific survival (CSS) in patients with malignant ovarian germ cell tumors, investigators found a 97% 5-year CSS in those with ovarian dysgerminoma compared with a 92% 5-year CSS for those with non-dysgerminoma. [2] Significant prognostic factors for cause-specific mortality in ovarian dysgerminoma included age older than 40 years at diagnosis and metastatic disease. In addition, a second cancer occurred in 10% of all patients who survived to 10 years and had received radiotherapy compared to 2% of those who had not received radiation treatment (P = .002).

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Patient Education

Educate patients about the importance of follow-up care during the first 2 years after initial therapy because 90% of recurrences manifest during this time.

Prior to and following chemotherapy, discuss with patients the potential for lung toxicity with bleomycin and the rare occurrence of secondary leukemias.

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