Medulloblastoma Clinical Presentation

Updated: Jan 10, 2018
  • Author: George I Jallo, MD; Chief Editor: Amy Kao, MD  more...
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Presentation

History

The majority of medulloblastomas occur as sporadic cases, yet hereditary conditions have been associated with medulloblastoma, including (1) Gorlin syndrome (nevoid basal-cell carcinoma syndrome), (2) blue rubber-bleb nevus syndrome, (3) Turcot syndrome (i.e., glioma polyposis syndrome), and (4) Rubinstein-Taybi syndrome.

Symptoms are often progressive over weeks to months, and it is not uncommon for patients to have an extended symptomatic period prior to initial diagnosis. Metastatic disease is commonly present at diagnosis (40%), and imaging of the entire craniospinal axis is an essential part of the initial diagnostic evaluation. [8]

Symptoms usually differ by anatomic location of the tumor, presence of disseminated disease, and by the presence of hydrocephalus.

Hydrocephalus

Patients with medulloblastoma most commonly have symptoms related to increased intracranial pressure (as a consequence of hydrocephalus). Symptoms usually precede presentation by no more than 2 months.

Presenting symptoms are related to the age of the patient. The younger, nonverbal patient presents with behavioral change. Symptoms in younger children include listlessness, irritability, vomiting, and decreased social interactions. Older children and adults complain of headache, especially upon awakening in the morning.

Vomiting without nausea is more common in the morning, since being recumbent (i.e., sleeping) increases intracranial pressure. Often, symptoms of headache and vomiting prompt an extensive and lengthy workup of the gastrointestinal tract prior to consideration of the CNS.

Patients may develop double vision as the sixth cranial nerve becomes stretched from the hydrocephalus. Visual disturbances more commonly are a result of papilledema.

Cerebellar symptoms

Most commonly found in children, the tumor involves the cerebellar vermis and causes gait ataxia more readily than unilateral symptoms.

Adults more commonly harbor the histological variant of desmoplastic medulloblastoma, which arises in the cerebellar hemisphere. These patients often have symptoms of ipsilateral dysmetria.

Head tilt and neck stiffness, caused by meningeal irritation, are complications of tonsillar herniation below the foramen magnum. Alternatively, head tilt can result from trochlear nerve palsy caused by direct tumor compression.

Leptomeningeal dissemination

Presenting symptoms rarely are related to dissemination of tumor in the CSF.

Patients can complain of severe weakness from tumor compression of the spinal cord or nerve roots (eg, radiculopathy).

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Physical

See the list below:

  • Physiognomy
    • Increasing head circumference often is the only presenting symptom in infants.
    • Infants may have also full anterior fontanelles with split cranial sutures.
  • Funduscopic examination
    • Visual difficulty usually is due to papilledema; however, it also may originate from cranial nerve palsy (most commonly CN IV or VI).
    • Some studies have found papilledema (the most common physical finding) to be present in as many as 90% of patients.
  • Extraocular examination
    • As a consequence of hydrocephalus, the sixth cranial nerve can be compressed at the petroclival ligament, resulting in diplopia and lateral gaze paresis.
    • Fourth cranial nerve palsy can be detected on careful extraocular examination and should be considered in any patient with a head tilt.
    • Patients with fourth cranial nerve dysfunction have greatest difficulty when eyes are rotated medially and depressed (i.e., going down stairs). The fourth cranial nerve usually is compressed by direct tumor extension into the cerebral aqueduct.
    • Examination of the extraocular muscles may detect nystagmus, which, although nonspecific, can be related to a lesion of the cerebellar vermis.
  • Cerebellar signs
    • Medulloblastoma most commonly is located midline. Therefore, unilateral dysmetria is less common than either truncal ataxia or a wide-based gait. Latter symptoms are easily observable on tandem gait.
    • As stated previously, desmoplastic medulloblastoma is more common in adults and usually arises in the cerebellar hemisphere.
    • Signs of ipsilateral cerebellar dysfunction in the arm or the leg are more common in this subtype.
  • Torticollis: Head tilt can be a manifestation of either accessory nerve (cranial nerve eleven) or trochlear nerve (cranial nerve four) palsy.
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Causes

Debate exists over the cellular origin of medulloblastoma.

One hypothesis is that medulloblastoma arises from primitive multipotent cells of the external granular layer of the cerebellar velum. This is an area of germ cell origin that persists for the first year of life before involuting.

The second hypothesis is that medulloblastoma arises from multipotent cells in the subependymal-subventricular region and fetal pineal region.

Genetic and molecular biology are described elsewhere in the topic.

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Complications

The cerebellum is involved in many complex aspects of human behavior and function, and when it is disrupted or insulted, this can lead to significant sequelae in patients with posterior fossa tumors. Some of the complications are more common in the pediatric population. Some of the more common complications are:

  • Hemiplegia/hemiparesis
  • Cerebrospinal fluid leak
  • Cranial nerve dysfunction – Injury to cranial nerves ranging from CN IV–XII can occur with posterior fossa surgery. Symptoms can range from visual disturbances to swallowing difficulty to motor and sensory deficits.
  • Posterior fossa syndrome (PFS) – Occurs in approximately 25% of patients who underwent resection of their posterior fossa tumor (usually medulloblastoma) [9]

Symptoms of diminished speech progressing to mutism with associated irritability, emotional lability, truncal hypotonia and ataxia usually present by postoperative day two, however, can develop later. Signs of brainstem dysfunction may also be present. These symptoms were deemed moderate to severe in more than 90% of patients with identified cerebellar mutism syndrome (CMS). [7] There is a positive correlation between brainstem involvement of the tumor and the development of CMS. Patients with cerebellar mutism often show some improvement in symptoms over time, however, a considerable number had residual symptoms at one year follow-up. The eventual recovery of speech occurs for most, but with slowly improving dysarthria over many months. In addition to speech problems, a hallmark of the syndrome is behavioral changes, including regressed personality, apathy, and poverty of spontaneous movement. [9] There are no evidence-based recommendations for the pharmacologic treatment of PFS and treatment is usually supportive. There are publications suggesting the use of a partial dopamine agonist such as aripiprazole, that may have a role in treating mental status changes after posterior fossa tumor resection. [10]

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