Intracranial chondromas.

Intracranial chondromas are rare lesions. Four new cases are added to the previously recorded 122 cases. These tumors originate from rests of cartilaginous cells at sphenoethmoidal and sphenooccipital synchondroses. Clinically, the major symptom is lower cranial nerve palsy; proptosis and visual impairment can also occur. More than 60% of the lesions are calcified. Bone destruction is common. Angiography shows displacement of vessels but no tumor stain. Pneumoencephalography reveals displacement of basal cisterns and the ventricular system. A radionuclide brain scan may show abnormal uptake in the tumor. Computed tomography should prove useful in evaluating cerebral extension. Unusual features in our case material included the presence of associated aneurysms in one.