Extragonadal germ cell tumors have been documented to arise in midline locations, most commonly in the anterior mediastinum, retroperitoneum, and the pineal gland or suprasellar regions of the brain 1).

1)
van Battum P, Huijberts MS, Heijckmann AC, Wilmink JT, Nieuwenhuijzen Kruseman AC. Intracranial multiple midline germinomas: is histological verification crucial for therapy? Neth J Med. 2007 Nov;65(10):386-9. PubMed PMID: 18057461.