Ovarian sex cord–stromal tumors—a clinicopathological study of 72 cases from the Kiel Pediatric Tumor Registry

We analyzed 72 patients with ovarian sex cord–stromal tumors (OSCST) registered at the German Pediatric Tumor Registry in Kiel over a 20-year period. Juvenile granulosa cell tumors (JGCT, n=48) were the most frequent histological subtype. In addition, there were 14 Sertoli-Leydig cell tumors, 5 sclerosing stromal tumors, 2 sex cord tumors with annular tubules, 2 thecomas and 1 steroid cell tumor. Stage according to FIGO (International Federation of Gynecologists and Obstetricians) was Ia in 39 patients, Ic in 17 patients, II in 3 patients and III in 1 patient (60 patients with complete data). Compared with adult granulosa cell tumors, JGCT showed pronounced mitotic activity [mean 9.8 mitoses/10 high power field (HPF)], which was significantly higher than in other histological subtypes (2.7/10 HPF, P=0.001). Immunohistochemical analysis revealed frequent coexpression of vimentin (positive in 52/52 examined tumors), cytokeratin (27/33), and inhibin (19/20). Of patients, 12 with Ic or higher stage tumors received adjuvant cisplatinum-based chemotherapy. Event-free survival at 10 years was 0.88±0.05 (38/43 patients with follow-up data). Outcome significantly correlated with stage and mitotic activity (<20 versus ≥20 mitoses/10 HPF: event-free survival 1.0 versus 0.48±0.05, P=0.0001). In conclusion, this analysis confirms that the majority of patients with OSCST present at low tumor stage and that prognosis in these patients is excellent. Refractory tumors are characterized by high proliferative activity. Therefore, histopathological evaluation substantially contributes to risk assessment in patients with OSCST and might be useful for therapy stratification in prospective therapeutic protocols.