Peripheral nerve tumors show an interesting histologic variety despite being composed ofa limited array of cellular constituents. As we learn more about the interplay between the Schwann cells, perineurial cells, and ganglion cells that comprise these tumors, it is likely that we will better understand the biologic behavior of these important tumors. Key issues for the pathologist include distinguishing schwannomas from neurofibromas, ganglioneuromas from neurofibromas involving ganglia, and MPNSTs from cellular schwannomas or neurofibromas. The association of each of these tumors with genetic tumor disorders provides a unique window into discovering basic mechanisms of cell regulation and tumorigenesis that may ultimately shed light on the biology of a much wider array of human disease.