Medulloblastoma is the most common brain tumor of childhood. It is quite dangerous and its mortality is not low and therefore it deserves at least a short article.


There is no clear cause of the tumor occurrence. It is assumed that there is a genetic predisposition, which is necessary for the tumor formation. Higher incidence of medulloblastoma has been reported in children with certain genetic syndromes such as the Turcot syndrome and Gorlin syndrome. Medulloblastoma occurs more often in boys than in girls.


The tumor typically arises in the cerebellum, which is a part of the brain, located in the back of the head. The cerebellum controls the locomotion (precision targeting and direction of movements and maintaining the balance). The symptoms include disorders of fine movements such as difficulty in writing and disorders of motor coordination and balance. Tumor mass may penetrate into the spinal cord and cause incontinence of urine and stool, gait disorder and back pain. Large tumors may increase the intracranial pressure resulting in headache and vomiting. Medulloblastoma behaves very aggressively and often forms metastases in brain and in distant organs.


First suspicion is usually stated by a pediatrician who examines the child and finds any of the mentioned neurological disorders. The tumor may be visualized by an imaging method such as brain computed tomography or magnetic resonance imaging (MRI is preferred in children as it brings no radiation hazard). A spinal tap may be also performed to obtain a sample of cerebrospinal fluid for cytology (evaluating the presence of tumor cells).


It is not always possible to cure the tumor and the approach depends on its exact location and its size. Ideally, the tumor is removed by a neurosurgical intervention, but permanent symptoms may persist resulting from tissue damage of the cerebellum. The neurosurgery may be supported by radiotherapy and chemotherapy.


Jiri Stefanek, MD  Author of texts: Jiri Stefanek, MD
 Sources: basic text sources