Case Report: Ovarian dysgerminoma mimicking a sex cord-stromal tumor with hyperandrogenism: diagnostic challenges and molecular insights.

Ovarian dysgerminoma, a malignant germ cell tumor, rarely presents with endocrine manifestations. This report describes a rare case of an 8-year-old girl with virilization symptoms and markedly elevated serum testosterone, initially suggestive of a steroid-producing sex cord-stromal tumor. Histopathological examination revealed a dysgerminoma with highly unusual architectural patterns, including pseudoglandular, follicular, and tubular structures, along with prominent luteinized stromal cells. Immunohistochemistry was diagnostic, showing germ cell markers (SALL4+, OCT3/4+, CD117+) and β-HCG-positive syncytiotrophoblasts associated with inhibin-α-positive stroma, thus explaining the androgen excess. Molecular profiling revealed concurrent KRAS and CDK4 amplifications, providing a plausible mechanistic basis for the tumor's high proliferative index and aggressive behavior, and underscoring the biological heterogeneity underlying this rare presentation. The patient achieved sustained remission after surgery and chemotherapy during a follow-up period of five years and six months. This case underscores the significant diagnostic challenge posed by dysgerminomas mimicking sex cord-stromal tumors and highlights the critical role of an integrated diagnostic approach combining morphology, immunohistochemistry, and molecular profiling to avoid misdiagnosis and guide management.