Ultrastructural morphometry of neurosecretory granules in the neuroblastomas of paediatric patients

Abstract

Introduction: Peripheral neuroblastic tumours are among the most frequently detected tumours in paediatric patients. A correlation between the aggressiveness of these tumours and their clinical prognosis has been discovered. Neurosecretory granules containing neurotransmitters, an ultrastructural feature of neurons, were found in the cells of peripheral neuroblastic tumours, as well.Aim: The aim of this study was to compare the number of neurosecretory granules found in cells of tumours, with a favourable prognosis to the corresponding number in cells of tumours and with an unfavourable one with the use of transmission electron microscopy (TEM).Material and Methods: Ten tissue biopsies were obtained from paediatric patients diagnosed with peripheral neuroblastic tumours. The tumour samples were first frozen, then fixed in glutaraldehyde, and embedded in epoxy resin. Ultrastructural morphometric analysis was performed on ultrathin sections.Results: When observed under a transmission electron microscope (TEM), neurosecretory granules appear as round structures of a small diameter, with an electron dense centre surrounded by an electron lucent, peripheral halo. It was found that the cells of tumours with an unfavourable prognosis have more neurosecretory granules (141.2 ± 89.18 per 60 cells per sample, on average) in their cytoplasm than the cells of tumours with a favourable one (37.2 ± 41.17 per 60 cells per sample, on average). Conclusion:The larger number of neurosecretory granules found in cells of tumours with an unfavourable prognosis could potentially shed some light on the role these structures play in tumourigenesis of peripheral neuroblastic tumours.