The origin of acoustic neuromas

Small acoustic neuromas, operated on through transpetrosal approaches were studied by light and transmission electron microscopy. All schwannomas were found to interpenetrate the vestibular ganglion without a space or a capsule. In the abnormal ganglion areas, free tumour Schwann cells were observed. These results suggest that acoustic neuromas originate from the vestibular ganglion. The fact that the sheath of vestibular ganglion bipolar cells in man are devoid of myelin may account for the elective origin of acoustic neuromas in the Scarpa ganglion in the human.