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Dysembryoplastic Neuroepithelial Tumors (DNETs)

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Dysembryoplastic neuroepithelial tumors (DNETs) are rare benign tumors of the central nervous system that most commonly are diagnosed in patients under the age of 20. These tumors, which usually arise in the frontal or temporal lobes of the brain, often consist of multiple lumps and cysts, or fluid-filled sacs. They arise from oligodendrocytes, supporting cells in the brain.

Symptoms

DNETs are associated with seizures and cortical dysplasia, a disorganization of neurons that is observed in patients with epilepsy. Usually a DNET is diagnosed in patients with a long history of seizures that do not respond well to medication. The tumors may cause other symptoms, such as headache and nausea, and because these tumors occur in the region of the brain that controls thought, movement, and sensation, they can cause a range of other symptoms depending on their location.

Diagnosis

Physical examination and a complete history will be conducted to assess seizure history. As with other brain tumors, imaging studies are a key component in the diagnosis of DNETs. Magnetic resonance imaging (MRI) computed tomography (CT) scans are used. For either study, an agent that provides contrast in the image is administered intravenously so neurological surgeons can visualize the tumor against the normal brain in the background.

Treatment

The primary treatment for a DNET is surgical removal. Because these tumors are benign, most patients will do well after surgery even if the tumor removal is less than total. Special care must be taken not to allow the cyst contents to leak during surgery because this material can cause severe irritation and infection in the area around the brain. Radiation therapy and chemotherapy are not used in the treatment of DNETs.

This page was last updated on 09/14/04.