Ultrastructural studies on neuroblastoma: evaluation of cytodifferentiation and correlation of morphology and biochemical and survival data.
Fifteen cases of neuroblastoma, ganglioneuroblastoma and ganglioneuroma were studied by electron microscopy. Ultrastructural features of cytodifferentiation, including numbers of dense core neurosecretory granules (NSG) and neuritic processes, were used to evaluate variation within the neuroblastoma group to determine whether differences in cytodifferentiation exist where light microscopic variations are not evident. These studies revealed that undifferentiated neuroblastomas do show ultrastructural variations not evident by light microscopy. The ultrastructural findings for each case were compared with initial urinary catecholamine excretory patterns, the latter having recently been shown to have valuable prognostic significance. There was a positive correlation, in the undifferentiated neuroblastomas, between increased numbers of NSG and prognostically favorable biochemical excretory patterns. Conversely, low numbers of NSG were associated with an unfavorable biochemical pattern and fatal clinical course. These correlations between ultrastructural differentiation and the biochemical secretory pattern indicate that ultrastructural evaluation of undifferentiated neuroblastomas would appear to have prognostic value, particularly in cases lacking initial biochemical data or as an adjunct to biochemical studies.