Neuroblastoma and peripheral neuroectodermal tumors.

Peripheral neuroblastic tumors in childhood present unique problems in terms of diagnosis, classification, and histologic determinants of prognosis. The proper specimen handling of these neoplasms requires integration of gross and microscopic pathologic examination along with cytogenetic, immunohistochemical, and electron microscopy studies. The appropriate gross examination and processing of these tumors are described with particular emphasis on ancillary studies. Important special studies such as immunohistochemistry, flow cytometry, and genetic and molecular oncologic investigation are stressed, and the appropriate methods of processing materials for these studies are discussed. The handling of small biopsy specimens, fine-needle aspirates, or both is also addressed. The staging of neuroblastoma varies according to Pediatric Oncology Group and Children's Cancer Study Group systems, and the importance of obtaining appropriate information to satisfy either system is noted. Ancillary information for classification of neuroblastoma and related neoplasms is also presented.