Has anyone here heard of extragonadal germ cell cancer?

Yes: Yes, sure.Extragonadal germinal cell tumors are rare tumors, represent 5-10% of all germ cell tumor, that predominantly affect young males.Characterized by their location on the midline from the pineal gland to the coccyx, (most common in mediastinum) . In egct, no evidence of a primary malignancy is present in testes or ovaries . Seminoma accounts for 30-40% and carries the best survival rates.

Yes, many sites: Such tumors can occur outside testes and ovary including brain, chest, abdomen, or tailbone you may wish to visit the following site for more information. www.cancer.gov/cancertopics/types/extragonadal-germ-cell.