Treatment of cerebellar masses.

Cerebellar masses are a heterogenous group of conditions that can cause compression of the aqueduct or fourth ventricle, resulting in obstructive hydrocephalus, brainstem compression, and upward/downward herniation as a direct result of mass effect. Untreated lesions can be fatal in a few hours, but prompt and appropriate treatment of the mass effect can produce very good outcomes. These patients should be closely followed in a critical care setting that has rapid access to neurosurgical expertise. Medical measures to decrease brain edema should be taken, including elevation of the head of the bed and avoidance of hypo-osmolar solutions, hypercarbia, or hyperthermia. Osmotic diuretics should be initiated promptly in patients with clinical worsening and radiographic evidence of edema resulting in mass effect. However, medical measures should not delay surgical intervention, which should proceed as rapidly as possible when indicated. Cerebellar hemorrhages more than 3 cm in diameter and cerebellar hemispheric strokes involving more than one third of the hemisphere should be considered for early suboccipital craniotomy with decompression. Regardless of lesion size, neurologic deterioration and radiologic signs of obstructive hydrocephalus should call for emergency decompressive surgery with resection of hematoma or necrotic brain tissue. Ventriculostomy should be considered as a bridge to surgical decompression, given the theoretical concern of upward herniation mediated by supratentorial drainage in the face of an underlying posterior fossa mass lesion. Steroids are not indicated for cerebrovascular disease but should be used to treat vasogenic edema induced by tumor. Anticoagulation is reserved for cerebellar venous and dural sinus thrombosis. Specific treatments targeting the underlying pathology should be used aggressively: thrombolysis and endovascular interventions for eligible stroke patients, antibiotic therapy for abscesses, and radiotherapy, chemotherapy, or both for tumors.