Dysembryoplastic neuroepithelial tumor (DNET) in a patient with Noonan syndrome

Introduction: The Noonan syndrome forms part of the dysmorphogenetic syndromes and is characterized by short stature, congenital heart defects, learning problems, and a characteristic configuration of facial features.

Clinical manifestations are very variable and include a broad spectrum of different morphological pathologies. Intracerebral dysmophisms have not been described so far.

Casuistics: The 13 year old patient with Noonan syndrome was introduced to our neuropediatric outpatient department because of recurrent, right-sided paroxysmal paresthesia, each lasting for about 15 seconds.

Showing delayed groth rate at the age of 6 years, medical workup brought the genetically proven diagnosis of Noonan syndrome.

Clinical examination showed no neurological disorders.

The cranial MRI showed an approximately 3×3x 2cm measuring lesion in the left parietal lobe. There were no signs of compression. Morphologically the finding corresponded most likely to a dysembryoplastic, neuroepithelial tumor.

Judging from the localization of the tumor we concluded, that this was the origin of the described paroxysmal sensory sensations in terms of symptomatic partial epilepsy.

Anticonvulsive therapy was initiated.

After repeated consideration of possible risks, growth hormone therapy was started one year after the initial diagnosis. MRI-control 4 months after initiation of therapy showed no progress in size.

Conclusion: There is no other case report of cerebral deformity tumors in patients with Noonan syndrome in literature.

Nevertheless neuro-imaging is highly indicated in Noonan patients with neurological symptoms an in any case before starting growth hormone therapy because of possible coincidence of both diseases.