Figure 1

Photomicrographs of MYCN amplified neuroblastoma demonstrating: A. Poorly differentiated neuroblasts with irregular nuclear outline and moderately sized nucleoli. The cytoplasm is scant and contains a few mitochondria and numerous polyribosomes with no evidence of cell junctions. Neuritic (cytoplasmic) processes are sparse and occasional neurosecretory granules are present in the cell cytoplasm. Original magnification ×1500. B. Rudimentary neurites are present in this area of the micrograph with numerous microtubules but no neurosecretory granules, emphasising the lack of differentiation. Often solitary mitochondria are also seen in the cytoplasmic process. Original magnification ×5000. C. Higher magnification shows microtubules in transverse and longitudinal orientation. Their mean diameter was 22.5 nm. Original magnification ×25000.