Subependymoma of the brain is a rare, slow-growing, and typically benign tumor of the central nervous system (WHO Grade I). Frequently these tumors arise within the ventricles and do not invade the brain parenchyma. Most patients are asymptomatic and subependymomas are often incidentally discovered in adults aged 50–60 years.
Subependymomas are most commonly localized in the fourth ventricle, can occur in the lateral ventricles, and rarely appear in the third ventricle. They are typically small, measuring 1–2 cm in diameter.
Subependymoma Symptoms
Due to their slow growth, subependymomas are often asymptomatic. Symptoms, when present, are usually related to the size of the tumor and the pressure it exerts on the ventricles and surrounding structures. Progressive tumors can cause increased intracranial pressure.
Headache: Chronic, often more pronounced in the morning, and may worsen with physical activity.
Visual disturbances: Increased intracranial pressure may lead to diplopia, blurred vision, or other visual symptoms.
Obstructive hydrocephalus: Tumors in the fourth ventricle may impede cerebrospinal fluid (CSF) flow, causing severe headache, nausea, vomiting, gait and balance disturbances, and, in some cases, altered consciousness.
Fourth ventricle tumors: Often associated with balance disturbances and brainstem compression symptoms.
Neurological deficits (rare): May occur if the brainstem or surrounding structures are compressed.
Lateral ventricle tumors: More likely to present with headache and cognitive changes.
Diagnostic Workup
Neurological Examination: A comprehensive evaluation of motor, sensory, cranial nerve, and reflex functions is essential.
Magnetic Resonance Imaging (MRI): MRI is the gold standard for diagnosing subependymomas. Tumors are typically small (1–2 cm) and localized in the fourth ventricle, although they may occasionally be found in the lateral or third ventricles.
Treatment Modalities
1. Surgical Resection (Microsurgical or Endoscopic)
Symptomatic subependymomas can be removed surgically. Even partial resection generally provides an excellent prognosis.
2. Ventriculoperitoneal (VP) Shunt
In cases where subependymomas obstruct CSF flow and cause hydrocephalus, a VP shunt can relieve intracranial pressure and associated symptoms such as headache, nausea, and visual disturbances by diverting excess fluid to the abdominal cavity.
3. Observation
Asymptomatic tumors can be managed conservatively with periodic neurological evaluations and imaging follow-up.
Subependymoma Life Expectancy
Due to their slow growth and benign nature, subependymomas typically do not adversely affect life expectancy. Complete surgical resection is associated with a low risk of recurrence, and most patients maintain normal quality of life. Long-term follow-up studies demonstrate that the majority of patients remain healthy for many years post-diagnosis.