We have recently found labyrintine ossification throughout the posterior semicircular in a case of acoustic neurinoma. We discussed the pathogenesis and histopathology of this lesion. Although, we regarded the chronic partial obstruction of blood circulation by the tumor in the internal auditory meatus as the cause of the labyrintine ossification, there still remain the unsolved problems on this subject. Moreover, we mentioned the possibility of the preoperative diagnosis for this lesion by means of X-ray, CT or MRI.
