[Peculiar forms of benign tumors of the brain stem].

Three patients are described, who were treated because of tumors of the medulla oblongata, growing towards the lumen of the IV ventricle and into the subarachnoid space. In two cases clinical cure was achieved after partial removal of the tumor and radiotherapy. One of these patients 32 years after the operation is working as a librarian, the other one treated 25 years ago is also professionally active and has a 5-year old son. In the third case only fragments of the tumor were taken for histological examination but radiotherapy was not given in view of serious condition of the patient. The patient however improved and after 23 years he died suddenly from myocardial infarction. On the base of these cases and a survey of the world literature it may by supposed that there are two kinds of brain stem tumors differing in their clinical course and direction of growth. Type A develops in the transverse plane of the brain stem and along its longitudinal axis producing paralysis of cranial nerves, signs of damage to the long ascending and descending pathways and disturbances of equilibrium. Symptoms of intracranial hypertension appear late or not at all. Type B grows into the lumen of the fourth ventricle and subarachnoid space as well, without infiltrating the deep structures of the brain stem. Partial removal of the tumor followed by radiotherapy may give useful survival for many years and may be even permanent cure.