Germ cell tumors.

Germ cell tumors in children are different from those in adults and often differ from each other in the site of the tumor and the age of the child. The appropriate gross examination and processing of these tumors by pathologists are described, and differences according to site and/or age are highlighted. Useful special studies such as immunohistochemistry and cytogenetics are identified, and the appropriate methods for processing material for these studies are discussed. Handling of small biopsy specimens or fine-needle aspirates is also addressed. Staging of germ cell tumors by site according to Pediatric Oncology Group and Children's Cancer Study Group treatment protocols and the most recent adaptation of grading of immature teratomas are outlined.