A case of pediatric ovarian dysgerminoma associated with high serum levels and positive immunohistochemical staining of neuron-specific enolase.

A 5-year-old girl presented with a painful abdominal mass. Abdominal magnetic resonance imaging (MRI) showed 3 separate masses. Tumor markers including lactate dehydrogenase (LDH), cancer antigen-125 (CA-125), beta-subunit of human chorionic gonadotropin (beta-hCG) and neuron-specific enolase (NSE) were elevated. At operation, the main tumor arose from the left ovary and was associated with torsion, whereas the other lesions were lymph node metastases. A salpingo-oophorectomy was performed. Histopathologic examination indicated that the tumor was a dysgerminoma. Immunohistochemicallly, the cells were positive for NSE and placental alkaline phosphatase (PALP) but were negative for CA-125, beta-hCG, S-100, glial fibrillary acidic protein, and vimentin. The elevated serum levels of tumor markers improved dramatically after the operation and chemotherapy.