Various Tumors in the 4th Ventricle in Adults: MRI Findings

Primary fourth ventricular neoplasms are common in children but rare in adults, and the disease categories encountered differ according to the patient's age. This study reviewed the records of patients aged 16 years or over, who underwent magnetic resonance (MR) imaging and were found to have fourth ventricular lesions. Most patients then underwent surgical resection, leading to specific pathologic diagnosis. The various fourth ventricular tumors encountered were ependymoma (n=8), subependymoma (n=1), choroid plexus papilloma (n=3), astrocytoma (n=3), medulloblastoma (n=1), lymphoma (n=2), epidermoid cyst (n=2), meningioma (n=1), melanoma (n=1), cavernous hemangioma (n=1) and metastasis (n=1). We describe the various tumors located mainly in the fourth ventricle and review their clinical presentation and the radiological findings, the majority of which were nonspecific. In some cases, however, specific signal intensity or the growth pattern of the tumors was useful for differential diagnosis.