Ganglion cell maturation in peripheral neuroblastic tumours of children

Peripheral neuroblastic tumours of neural crest origin are the most frequent solid neoplasms outside the CNS in children. Neuroblastoma/ganglioneuroblastoma/ganglioneuroma have a natural evolution of histological differentiation over time. Together with mitosis-karyorrhexis index and patient age (International Neuroblastoma Pathology Classification criteria), ganglion cell maturation determines grading and prognosis. Maturation presently is usually assessed only histologically. Immunocytochemical tissue markers defining neuroblast maturation in fetal CNS were here applied to peripheral neuroblastic tumours arising in the adrenal medulla or sympathetic chain. Paraffin sections of resected tumours of 4 toddlers were examined using antibodies demonstrating neuronal identity and maturation: MAP2; synaptophysin; chromogranin-A; NeuN; keratan sulfate (KS); glutamate receptor antibody (GluR2). Synaptophysin, normally a late marker of neuroblast differentiation, was the earliest expressed in neuroblastoma. Others include: Ki67; S-100β protein; vimentin; nestin; α-B-crystallin; neuroblastoma marker PHOX2B. Various degrees of ganglion cell maturation were demonstrated by MAP2, chromogranin, synaptophysin, KS, and GluR2; NeuN was uniformly negative, consistent with sympathetic neurons. KS was sparsely distributed within the tumours in interstitial tissue, within processes of some non-neuronal cells, and adherent to somata and proximal neuritic trunks. Neoplastic ganglion cells with multiple nuclei matured similar to mono-nuclear forms. PHOX2B did not distinguish maturational stages. S-100β protein and α-B-crystallin labeled Schwann cells, especially Schwannian ganglioneuroma. Immunocytochemical markers of neuroblast maturation in fetal brain also are useful in peripheral neuroblastic tumours, providing greater precision than histology alone. The most practical are MAP2, chromogranin-A, and synaptophysin. Prognosis and choice of treatment including chemotherapy might be influenced.