Germ cell tumors of the ovary comprise fewer than 5% of all malignant ovarian tumors. Germ cell tumors arise from the primordial germ cells and sex cord-stromal derivatives; they are exceedingly common in that they account for approximately one-quarter of all ovarian tumors, yet only 1% to 5% of germ cell tumors are malignant.1,2,3,4, and 5 This disease is characterized by a young age at diagnosis. Survival is excellent due to the typically early stage at diagnosis and the relative chemosensitivity of even advanced disease, especially in comparison with epithelial ovarian, tubal, and peritoneal cancers.
The peak incidence of these tumors occurs in the 15- to 19-year-old age range.
Germ cell tumors may occur in setting of dysgenetic gonads, so karyotype testing may be warranted.
Within the United States, the incidence (age-adjusted) of malignant germ cell tumors is estimated at between 0.34 to 0.41 per 100,000, and rates appear to have declined over the last 30 years.1,2 Risk factors are not well understood, but include younger age; the 15- to 19-year-old age group has by far the highest incidence rates. Studies have not consistently confirmed other specific demographic characteristics, such as in utero exposures (hormones, pesticides, smoking, or alcohol), maternal reproductive history, parental occupation, or congenital abnormalities as associated risk factors for germ cell tumors.6,7, and 8 Racial differences exist in that dysgerminoma occurs twice as often in whites and other nonwhites as compared with blacks, and teratoma incidence is increased for blacks and other nonwhites as compared with whites; there appear to be no significant differences for the remainder of types.2,9
As opposed to some epithelial and stromal ovarian malignancies, germ cell tumors in females do not appear to be related to any yet-identified inherited cancer susceptibility syndromes (eg, BRCA mutations for epithelial ovarian, tubal, and peritoneal cancers and Peutz-Jegher syndrome for certain ovarian stromal tumors).10 Surprisingly, in a recent review of pediatric germ cell tumors, a family history of testicular cancer was correlated with an increased risk of male germ cell tumors; however, a family history of ovarian or uterine cancer was inversely correlated with female germ cell tumors.10 In contrast, there have been several case reports of familial clustering of germ cell tumors, and authors have hypothesized that a fraction of ovarian germ cell tumors could be a rare manifestation of a familial gonadal tumor syndrome.11
Of particular note, however, is that women with gonadal dysgenesis are at very high risk for the development of germ cell tumors. Gonadal dysgenesis is defined as a defect in development that causes abnormal sex steroid production and subsequent clinical manifestations such as delayed puberty or primary amenorrhea. In general, Turner syndrome (normally 45 ...