A 9-year-old boy is brought to the emergency department after having a seizure at school. His teacher says he suddenly fell to the ground with sustained flexion of the arms and extension of the legs, followed by clonic movements of his whole body for 5 minutes. The patient appeared sleepy after the episode, but his behavior is now at baseline. His parents arrive shortly after and note that the boy has been increasingly tired and irritable over the last few months, and his school performance has declined this semester. The patient has no medical issues and takes no medications. Physical examination shows decreased muscle strength on the left side of the body, with brisk deep-tendon reflexes in the left arm and leg. Visual field examination is normal. MRI of the brain reveals a space-occupying lesion in the right parietal lobe. Which of the following is most likely responsible for this patient's symptoms?

Question

A 9-year-old boy is brought to the emergency department after having a seizure at school.  His teacher says he suddenly fell to the ground with sustained flexion of the arms and extension of the legs, followed by clonic movements of his whole body for 5 minutes.  The patient appeared sleepy after the episode, but his behavior is now at baseline.  His parents arrive shortly after and note that the boy has been increasingly tired and irritable over the last few months, and his school performance has declined this semester.  The patient has no medical issues and takes no medications.  Physical examination shows decreased muscle strength on the left side of the body, with brisk deep-tendon reflexes in the left arm and leg.  Visual field examination is normal.  MRI of the brain reveals a space-occupying lesion in the right parietal lobe.  Which of the following is most likely responsible for this patient's symptoms?

Quizplus · Accepted Answer

11ec25c8_d595_e531_bc81_4d6419b5b779_MD0003_00 Central nervous system (CNS) tumors are the second most common pediatric malignancies after leukemia and the most common pediatric solid tumors. Tumors originating in the cerebral cortex (ie, supratentorial) classically present with headache due to increased intracranial pressure; however, new-onset seizure may be the presenting symptom, as seen in this patient. Changes in speech, memory, and personality (eg, irritability, declining academic performance) can also occur with supratentorial masses, and hemiparesis and hyperreflexia are common with parietal lobe involvement (as in this patient). Central nervous system (CNS) tumors The most common brain tumor in children is low-grade astrocytoma. Astrocytomas are derived from astrocytes (the dominant glial cell in the brain) and can be low or high grade. Low-grade astrocytomas (eg, pilocytic astrocytoma, diffuse astrocytoma) are typically slow-growing and benign, causing symptoms to develop over many months (as in this patient). High-grade astrocytomas (eg, glioblastoma) are malignant and much less common than low-grade astrocytomas (Choice C). In contrast to the patient's presentation, this aggressive tumor type causes symptoms over days to weeks, not months. (Choice A) Craniopharyngiomas arise in the sella turcica and appear as cystic structures with calcifications on imaging. Local compression of the optic chiasm and pituitary stalk may lead to visual field defects and hormonal deficiencies (eg, growth hormone), respectively. A parietal lobe mass would not be seen. (Choice B) Ependymomas arise from the ependymal cell lining of the ventricles and spinal cord. In children, the most common intracranial site is the fourth ventricle in the posterior fossa (not cerebral cortex). In addition, ependymomas are far less common than low-grade astrocytomas. (Choice E) Medulloblastoma is one of the most common pediatric posterior fossa tumors and typically arises from the cerebellar vermis. Presentation includes ataxia due to involvement of the cerebellum (not cerebral cortex). (Choice F) Neuroblastomas arise from sympathetic ganglion cells and usually present with an abdominal mass. Although end-stage disease can metastasize to the brain, primary pediatric CNS tumors are much more common than CNS metastases, making this diagnosis unlikely. Educational objective: In children, low-grade astrocytomas are the most common type of central nervous system tumor. New-onset seizures may be the initial presentation of a tumor originating in the cerebral cortex. References: Childhood brain tumor epidemiology: a brain tumor epidemiology consortium review. (http://www.ncbi.nlm.nih.gov/pubmed/25192704) Childhood brain tumors: epidemiology, current management and future directions. (http://www.ncbi.nlm.nih.gov/pubmed/21788981) Pediatric low-grade gliomas. (http://www.ncbi.nlm.nih.gov/pubmed/19841428)

A 9-Year-Old Boy Is Brought to the Emergency Department After