Inflammatory myofibroblastic tumor of the cerebellar hemisphere--case report.

A 60-year-old man presented with a rare cerebellar inflammatory myofibroblastic tumor (IMT) manifesting as gait disturbance and dysarthria. Brain magnetic resonance imaging demonstrated an intra-axial round-shaped isointense mass homogeneously enhanced with gadolinium in the right cerebellar hemisphere, as well as perifocal edema extending to the brain stem and right thalamus. The tumor was elastic hard and was resected en bloc with a clear margin. Histological examination revealed IMT with spindle cells and collagen, but negative for anaplastic lymphoma kinase expression. IMT most commonly affects the lung, but may involve many other parts of the body. There is some debate regarding the disease entity of IMT in the central nervous system (IMT-CNS) because of its rarity and high frequency of recurrence. IMT-CNS is an important differential diagnosis among tumor-like intracranial lesions and total resection is required.