Growing teratoma syndrome in pediatrics.

Growing teratoma syndrome (GTS), described by Logothetis in 1982, is characterized by the appearance of benign tumor lesions during or after chemotherapy for germ cell tumors, with normalized tumor markers. It is rare in pediatrics; in Mexico, there have been no previous reports of this condition in girls. We present an 8-year-old girl with abdominal distension, colicky pain, and constipation; a CT scan revealed a mass in the right ovary, a liver lesion, and intra-abdominal fluid. Cytoreductive surgery revealed an immature teratoma with neuroglial implants. She was diagnosed with stage IV mixed germ cell tumor; chemotherapy was initiated. Given the persistence of a residual mass with normalized tumor markers, laparotomy confirmed mixed germ cell tumor. Since complete resection was not possible, close monitoring was decided upon; she remains stable at 11 months. GTS should be considered in pediatric germ cell tumors with tumor growth and normalized markers. Surveillance is a valid alternative in unresectable cases.