How is pediatric neuroblastoma diagnosed?

Updated: Oct 09, 2017
  • Author: Norman J Lacayo, MD; Chief Editor: Max J Coppes, MD, PhD, MBA  more...
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Answer

Biopsy findings are usually required to diagnose neuroblastoma. Depending on the extent of disease at presentation, consider complete surgical resection, especially in patients with low-stage disease. Even without a biopsy, the presence of elevated urinary catecholamines and a bone marrow aspirate or biopsy with unequivocal neuroblastoma cells is diagnostic.

Histologically, neural crest tumors can be classified as neuroblastoma, ganglioneuroblastoma, and ganglioneuroma, depending on the degree of maturation and differentiation of the tumor. Undifferentiated neuroblastomas histologically present as small, round, blue cell tumors with dense nests of cells in a fibrovascular matrix and Homer-Wright pseudorosettes. These pseudorosettes, observed in 15-50% of tumor samples can be described as neuroblasts surrounding eosinophilic neuritic processes. The typical tumor shows small uniform cells with scant cytoplasm and hyperchromatic nuclei. A neuritic process, also called neuropil, is a pathognomonic feature of neuroblastoma.

Neuron-specific enolase (NSE), chromogranin, synaptophysin, and S-100 immunohistochemical stain findings are usually positive. Electron microscopy can be useful because ultrastructural features (eg, neurofilaments, neurotubules, synaptic vessels, dense core granules) are diagnostic for neuroblastoma. In contrast, the completely benign ganglioneuroma is typically composed of mature ganglion cells, Schwann cells, and neuritic processes, whereas ganglioneuroblastomas include the whole spectrum of differentiation between pure ganglioneuromas and neuroblastomas.

The pathologist must thoroughly evaluate the tumor because regions with different gross appearance may exhibit a different histology.


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