Epithelial ovarian neoplasia
Ovarian tumors derived from malignant epithelial elements include: adenocarcinomas, cystadenocarcinomas, endometrioid tumors, clear cell tumors, and undifferentiated carcinomas. In one series of 19 patients younger than 21 years with epithelial ovarian neoplasms, the average age at diagnosis was 19.7 years. Dysmenorrhea and abdominal pain were the most common presenting symptoms; 79% of the patients had stage I disease with a 100% survival rate, and only those who had small cell anaplastic carcinoma died.
Girls with ovarian carcinoma (epithelial ovarian neoplasia) fare better than adults with similar histology, probably because girls usually present with low-stage disease.
Treatment is stage-related and may include surgery, radiation, and chemotherapy with cisplatin, carboplatin, etoposide, topotecan, paclitaxel, and other agents.
Sex cord–stromal tumors
Ovarian sex cord–stromal tumors are a heterogeneous group of rare tumors that derive from the gonadal non-germ cell component. Histologic subtypes display some areas of gonadal differentiation and include juvenile granulosa cell tumors, Sertoli-Leydig cell tumors, and sclerosing stromal tumors. Ovarian sex-cord stromal tumors in children and adolescents are commonly associated with the presence of germline DICER1 mutations and may be a manifestation of the familial pleuropulmonary blastoma syndrome.
Juvenile granulosa cell tumors
The most common histologic subtype in girls younger than 18 years is juvenile granulosa cell tumors (median age, 7.6 years; range, birth to 17.5 years).[29,30] Juvenile granulosa cell tumors represent about 5% of ovarian tumors in children and adolescents and are distinct from the granulosa cell tumors seen in adults.[27,31,32,33]
Most patients with juvenile granulosa cell tumors present with precocious puberty. Other presenting symptoms include abdominal pain, abdominal mass, and ascites. Juvenile granulosa cell tumors has been reported in children with Ollier disease and Maffucci syndrome.
As many as 90% of children with juvenile granulosa cell tumors will have low-stage disease (International Federation of Gynecology and Obstetrics [FIGO] stage I) and are usually curable with unilateral salpingo-oophorectomy alone. Patients with advanced disease (FIGO stage II–IV) and those with high mitotic activity tumors have a poorer prognosis.
Use of a cisplatin-based chemotherapy regimen has been reported in both the adjuvant and recurrent disease settings with some success.[29,33,36,37,38]
Sertoli-Leydig cell tumors
Sertoli-Leydig cell tumors are rare in young girls but may present with virilization  or precocious puberty.[40,41] These tumors may also be associated with Peutz-Jeghers syndrome. In contrast to juvenile granulosa cell tumors, a recent study suggested that Sertoli-Leydig tumors with abdominal spillage (FIGO Stage Ic) should be treated with cisplatin-based chemotherapy.
Small cell carcinoma of the ovary
Small cell carcinomas of the ovary are exceedingly rare and aggressive tumors and may be associated with hypercalcemia. Successful treatment with aggressive therapy has been reported in a few cases.[Level of evidence: 3iiB]; [44,45][Level of evidence: 3iiiA]