Bifocal mixed germ-cell tumor with growing teratoma syndrome and metachronous mature metastases: case report.

The authors report the case of a 16-year-old male who presented with a bifocal diencephalic tumor arising both in the neurohypophysis and the pineal region with hydrocephalus. The histological diagnosis obtained during endoscopic ventriculocisternostomy was germinoma. MRI revealed an increase of the neoplasm during chemotherapy with recurrent obstructive hydrocephalus. A new ventriculostomy was performed followed by total surgical resection. The final histopathological analysis demonstrated an immature teratoma. Subsequently, this patient developed metachronous cystic metastases in the cerebello-pontine angles, which were resected and identified as mature teratoma, then we observed a lesion of the brachium conjunctivum which stayed stable after 29 consecutive months. The patient is alive and feels well 6 years after the initial diagnosis and 5 years after the first metastasis. To our knowledge, this is the fifth case of the growing teratoma syndrome located in the brain but the first case with simultaneously bifocal location and infratentorial disseminated metastasis. Obviously surgical removal is the treatment of reference for teratomas. Metastases of teratoma can be mature and may be amenable to surgery with a favorable outcome. Primary intracranial germ-cell tumors (CGT) arise in the midline of the brain and are located in the diencephalon. The peak incidence occurs during the second decade of life. Germ cell tumor (CGT) includes germinomas and non-germinomatous tumors, mature and immature teratomas account for 19.6 % [1]. Curiously, teratomas are able to grow during the first weeks of chemotherapy while serum markers remain normal. This situation was originally described and designed as "the growing teratoma syndroma" (GTS) in primary testis tumors by Logothetis in 1982 [2]. Here we report the rare occurrence of a GTS in a teenager who presented metachronous cystic metastases located in posterior fossa which were histologically mature.