Ganglioneuromas have a uniform appearance consisting of longitudinal and transversely oriented bundles of Schwann cells in a myxoid stroma. Relatively mature ganglion cells are scattered throughout the tumor in small nests and clusters. It is important to do a thorough sampling of the tumor and submit sections from any heterogenous or hemorrhagic areas so as not to miss less differentiated areas which would change the diagnosis to ganglioneuroblastoma.
There may be considerable variation in the distribution and density of ganglion cells. Tumors with sparse number of ganglion cells may be misdiagnosed as neurofibromas. The ganglion cells are not fully mature and lack satellite cells and Nissl bodies. They contain one to three nuclei and may show mild to moderate atypia.