Any tumor derived from the cells of the nervous system.
Two types : False neuroma & True neuroma
False neuroma :
It occurs due to injury to a nerve following a trauma or amputation which presents as a tender swelling.
It arises from connective tissue of nerve sheath.
It can be end neuroma, commonly seen in amputation stump as a tender localised firm swelling often adherent to the stump scar. It can cause neuralgia in the stump.
True neuroma :
It is rare tumor which occurs in connection with sympathetic system.
It contains ganglion cells and nerve fibres
It occurs in connection with sympathetic chain. So it is observed in neck, thorax, retroperitoneum
It is relatively benign and symptomless
It is poorly differentiated, aggressive, embryonic type of tumor
It is seen in infants and children
It spreads through blood
Myelinitic neuroma :
It contains only nerve fibres
Ganglion cells are absent
It occurs in spinal cord and pia mater