A 10-year-old boy is brought to the clinic due to headache, vomiting, and visual disturbances. The patient has had 2 weeks of persistent headache; he was given over-the-counter analgesics but had no relief. He has also had daily episodes of nonbloody, nonbilious emesis. Neurologic examination shows bilateral retraction of the upper eyelids and limitation of upward gaze with a preference for downward gaze. Pupils react sluggishly to light but respond appropriately to accommodation. Strength, sensation, and deep tendon reflexes are normal. Gait is normal. Plantar reflexes are downgoing bilaterally. Which of the following lesions is most likely responsible for this patient's symptoms?
Clinical features of pineal gland masses | |
Parinaud |
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Obstructive |
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This patient's persistent headache and ocular abnormalities are concerning for a pineal gland tumor, or pinealoma. The pineal gland is in the quadrigeminal cistern and is responsible for melatonin production. Pineal gland tumors are rare, and germ cell tumors account for most masses. Children age 1-12 are most commonly affected.
Symptoms of pineal tumors are typically caused by mass effect. Parinaud syndrome (or dorsal midbrain syndrome) results from pressure on the pretectal region of the midbrain near the superior colliculus and the oculomotor nerve (CN III). Classic examination findings include limitation of upward gaze (ie, downward gaze preference) and light-near dissociation (ie, pupils reactive to accommodation but not to light), as seen in this patient. Patients also typically have bilateral eyelid retraction (ie, Collier sign), resulting in visible sclera above the superior corneal limbus.
Pineal gland masses often block cerebrospinal fluid flow in the aqueduct of Sylvius, causing obstructive hydrocephalus. Papilledema, headache, and vomiting can occur due to increased intracranial pressure. Progressive hydrocephalus may also lead to ataxia.
(Choice A) Craniopharyngiomas are suprasellar masses that can compress the optic chiasm, causing visual field deficits. They are not associated with Parinaud syndrome.
(Choice B) Pediatric medulloblastomas usually arise from the cerebellar vermis and present with ataxia and truncal instability. In rare cases, obstructive hydrocephalus due to medulloblastoma can cause increased pressure at the pretectal region and Parinaud syndrome, but it is unlikely in this patient with a normal gait.
(Choice C) Neuroblastomas arise from the sympathetic nervous system and are usually located in the adrenal glands; intracranial tumors are rare. Opsoclonus-myoclonus syndrome (antibody-mediated "dancing eyes and feet") can occur but not Parinaud syndrome.
(Choice E) Retinoblastoma is an intraocular tumor most commonly seen in children age <5. A trilateral retinoblastoma consists of bilateral retinoblastoma and a pineal gland tumor. It is rare, especially in an older child, and typically presents with leukocoria.
Educational objective:
Parinaud syndrome occurs in most patients with pineal gland masses (pinealomas) and presents as limitation of upward gaze, bilateral eyelid retraction, and light-near dissociation. Pineal gland tumors can also cause persistent headache and vomiting due to obstructive hydrocephalus.