Approach to a suspected brain tumor (pediatrics): Clinical sciences

Brain tumors are histologically diverse and can range from indolent, benign tumors to aggressive, infiltrating malignancies. Although both benign and malignant brain masses are associated with significant neurologic morbidity, they often present with nonspecific, vague, or intermittent symptoms. These symptoms are related to tumor location, disruption of neurologic function, and the onset of increased intracranial pressure, or ICP.

When a pediatric patient presents with a chief concern suggesting a brain tumor, your first step is to perform an ABCDE assessment to determine if they are stable or unstable.

If unstable, stabilize the airway, breathing, and circulation. Consider intubating your patient if they demonstrate shallow, ineffective, or absent respirations. Then, obtain IV access and consider administering IV fluids. Finally, continuously monitor vital signs and, if needed, administer supplemental oxygen

Here’s a high-yield fact! An enlarging brain mass can obstruct cerebrospinal fluid drainage, causing elevated ICP. If not treated promptly, increased ICP can lead to brain herniation, which is associated with long term neurologic sequelae and death. Signs of increased ICP include bulging fontanelles; unilateral pupillary dilation, sometimes called a “blown pupil”; focal neurologic deficits; abnormal posturing; and the Cushing triad, which consists of bradycardia, a widened pulse pressure, and irregular respirations known as Cheyne-Stokes breathing.

Now that we have discussed unstable patients, let’s return to the ABCDE assessment and look at stable ones.

Your next step here is to obtain a focused history and physical examination. Presenting symptoms often include headaches, which usually start in the morning and are relieved by vomiting; nausea and vomiting; seizures; changes in school performance; or loss of developmental milestones.

The physical exam might demonstrate altered mental status; cranial nerve palsies; visual impairment; abnormal motor or sensory findings; hyperreflexia; or ataxia. Because cranial sutures remain open until the second year of life, patients presenting before 2 years of age might also present with a bulging fontanelle or macrocephaly, which can be noticed with elevated head circumference. With these findings, consider a brain tumor, and obtain an MRI of the brain to look for a mass. Then, assess your patient for localizing symptoms.

If history is significant for seizures, consider a hemispheric mass, such as glioblastoma multiforme or a primitive neuroectodermal tumor. In addition to seizures, these patients usually have focal weakness and sensory changes; possibly with changes in cognitive function, including behavior, personality, language, and speech. Older children might report headaches, while infants might demonstrate early handedness.

Exam findings might include an altered level of consciousness; motor weakness or paralysis, asymmetric reflexes; and vision or hearing loss. The MRI will confirm a hemispheric mass, possibly with infiltration into the surrounding tissues.

Once you've identified a mass, obtain a biopsy or resection with histology to confirm the diagnosis. If histology demonstrates dense cellularity, high mitotic index, microvascular proliferation, and foci of tumor necrosis, diagnose glioblastoma multiforme, which is an aggressive astrocytoma.

Here's a clinical pearl! The WHO classification system is used to grade central nervous system tumors from Grade I to Grade IV, which helps to determine overall treatment and prognosis.

Grade I tumors are benign and can be treated with resection, but Grade IV tumors are aggressive, infiltrating malignancies that often respond poorly to resection, radiation, or chemotherapy.

Okay, now back to biopsy results. If histology shows undifferentiated or poorly differentiated small, round, blue neuroepithelial cells, diagnose a primitive neuroectodermal tumor.

Here’s another clinical pearl! Another type of neuroectodermal tumor to keep in mind is an atypical teratoid or rhabdoid tumor. These rare, rapidly growing, malignant masses can appear anywhere in the central nervous system and usually occur in children under age five.

Okay, now that we've discussed hemispheric masses, let’s go back to our assessment of localizing symptoms. If the primary symptoms include headache and vomiting, particularly in the early morning, consider a midline or posterior fossa mass. Tumors in these areas are more likely to obstruct cerebrospinal fluid drainage and produce symptoms of increasing ICP.

To further localize the tumor, assess your patient for ataxia. If there's no evidence of ataxia, consider a midline mass, such as a suprasellar or pineal mass, and then assess your patient’s linear growth.

If linear growth is delayed, consider a suprasellar mass. History usually reveals visual changes, and vision loss due to pressure on the optic nerve; possibly combined with endocrine issues such as delayed puberty, diabetes insipidus, and thyroid dysfunction.

Common physical exam findings include visual field changes, papilledema, short stature, and poor weight gain. If the MRI confirms a heterogeneous solid and cystic suprasellar mass, obtain a biopsy or resection of the mass with histology.

If histology demonstrates a complex tumor with stratified cells, multiple cysts with thick “motor oil”-like fluid, cholesterol cysts, and keratin pearls, diagnose craniopharyngioma, a large but benign tumor.

On the other hand, if there's no delay in linear growth, consider a pineal mass, such as a pineal parenchymal tumor, benign germinoma, yolk sac tumor, choriocarcinoma, immature teratoma, or embryonal cell carcinoma.

Pineal masses often cause difficulty with eye muscle movement, leading to double vision; and occasionally, endocrine dysfunction, such as precocious puberty, diabetes insipidus, and thyroid dysfunction.