Malignant germ cell tumors (GCTs) and gonadal tumors are rare, with an incidence of 12 cases per million persons <20 yr of age. Most malignant tumors of the gonads in children are GCTs. The incidence varies according to age and sex.
Sacrococcygeal tumors occur predominantly in infant girls.
Testicular GCTs occur predominantly before age 4 yr and after puberty. Testicular GCTs occur much more often in whites than in blacks, whereas ovarian GCTs have a slight predominance in blacks.
Klinefelter syndrome is associated with an increased risk of mediastinal GCTs;
Down syndrome, undescended testes, infertility, testicular atrophy and inguinal hernias are associated with an increased risk of testicular cancer.
The serum ?-fetoprotein (AFP) level is elevated with endodermal sinus tumors and may be minimally elevated with teratomas. Infants have higher levels of AFP, which fall to normal adult levels by about 8 mo; therefore, high AFP levels must be interpreted with caution in this age group. Elevation of the ? subunit of human chorionic gonadotropin (?-hCG) is seen with choriocarcinoma and germinomas. Lactate dehydrogenase (LDH), although nonspecific, may be a useful marker. If elevated, these markers provide important confirmation of the diagnosis and provide a means to monitor the patient for tumor response and recurrence. Both serum and cerebrospinal fluid should be assayed for these markers in patients with intracranial lesions.
Diagnosis begins with physical examination and imaging studies, including plain radiographs of the chest and ultrasonography of the abdomen. CT or MRI can further delineate the primary tumor. If germ cell malignancy is strongly suggested, preoperative staging with CT of the chest and bone scan is appropriate. Primary surgical resection is indicated for tumors deemed resectable. The exception is intracranial lesions, where the diagnosis can be established with imaging and AFP or ?-hCG determinations.
Gonadoblastomas often occur in patients with gonadal dysgenesis and all or parts of a Y chromosome. Gonadal dysgenesis is characterized by failure to fully masculinize the external genitalia. If this syndrome is diagnosed, imaging of the gonad with ultrasonography or CT is performed, and surgical resection of the tumor usually is curative. Prophylactic resection of dysgenetic gonads at the time of diagnosis is recommended, because gonadoblastomas, some of which contain malignant germ cell tumor elements, often develop. Gonadoblastomas may produce abnormal amounts of estrogen.
Teratomas occur in many locations, presenting as masses. They are not associated with elevated markers unless malignancy is present. The sacrococcygeal region is the most common site for teratomas. Sacrococcygeal teratomas occur most commonly in infants and may be diagnosed in utero or at birth, with most found in girls. The rate of malignancy in this location varies, ranging from <10% in children <2 mo of age to >50% in children >4 mo of age.
Germinomas occur intracranially, in the mediastinum, and in the gonads. In the ovary, they are called dysgerminomas; in the testis, seminomas. They usually are tumor marker negative despite being malignant. Endodermal sinus or yolk sac tumor and choriocarcinoma appear highly malignant by histologic criteria. Both occur at gonadal and extragonadal sites. Embryonal carcinoma most often occurs in the testes.
Non-germ cell gonadal tumors are very uncommon in pediatrics and occur predominantly in the ovary. Epithelial carcinomas (usually an adult tumor), Sertoli-Leydig cell tumors, and granulosa cell tumors may occur in children. Carcinomas account for about ? of ovarian tumors in females <20 yr of age; most of these occur in older teens and are of the serous or mucinous subtype. Sertoli-Leydig cell tumors and granulosa cell tumors produce hormones that can cause virilization, feminization, or precocious puberty, depending on pubertal stage and the balance between Sertoli (estrogen production) and Leydig cells (androgen production). Diagnostic evaluation usually focuses on the chief complaint of inappropriate sex steroid effect and includes hormone measurements, which reflect gonadotropin-independent sex steroid production. Appropriate imaging also is performed to rule out a functioning gonadal tumor. Surgery usually is curative. No effective therapy for nonresectable disease has been found.