Ultrastructural finding in case of paraganglioma ?
Ans. is 'd' i.e. Dense core granules Para gangliomasThe paraganglioma have been known historically by a variety of names including glomus tumours, chemodectoma, non chromaffin paraganglioma, glomercytomas, carotid body and tympanic body tumours and receptoma.Essentially these tumours make up a family of neoplasms that develop from the para ganglial tissues which are actually chemoreceptor organs that are distributed throughout the body.These chemoreceptor organs are of neural crest origin and have similar functions and similar histological appearance.Their cells of origin are a part of the diffuse neuroendocrine system (DNES).Para gangliomas are composed of characteristic cell called 'C' cellThe chief cell is probably the principal component involved and seems to be the actual chemoreceptor of the paraganglia containing acetyl choline, catecholamine and serotonin.Chief cell is of neural crest origin and it contains hormone thus it is neuroendocrine in nature. It renders the paraganglia receptive to hypoxia and pH changes and to fluctuations in blood carbon dioxide concentration.These chief cells migrate with the autonomic ganglion cells. They are in close association with the sympathetic ganglia and Aorta in its main branches.Many head and neck paraganglia and their respective neoplasms are distributed in relation to the vessel and cranial nerves of the primitive branchial arches.Because of this they are also called branchiomeric paraganglioma.Pathology of paraganglioma:Like other neuroendocrine tumour the ultrastructure shows dense core granules (' neurosecretory granules')The tumour cells balls are arranged in distinctive cell balls called Zellballen (the cell balls are composed of chief cells).These cells are separated by fibrovascular stroma and surrounded by sustentacular cells. Immunohistochemistry of paragangliomaChief cells are neuroendocrine cells and are thus positive for regular neuroendocrine markers e.g.ChromograninSynaptophysinNeuron specific enolaseSerotoninNeurofilamentThe chief cells are S-100 protein negative but the sustentacular cells are S-100 positive and are focally positive for glial fibrillary acid protein.On histochemistry they are argyrophilic, PAS negative, mucicarmine negative and argentaffin negative.An important point in d/d is that they are never positive for cytokeratin like other neuroendocrine tumours.
Deposition of glycogen
Enlarged mitochondria
Shrunken mitochondria
Dense core granules
Peripheral Nerve & Skeletal Muscles