Abstract
INTRODUCTION: Gliomas of the cerebellum are rare in adults, and their natural history and clinical behavior are not well known. Because cerebellar glioma is not usually diagnosed until clinical symptoms have appeared, no reports have described the developmental process of new cerebellar gliomas. We describe a case of de novo cerebellar anaplastic astrocytoma in which the developmental process was detected on magnetic resonance imaging (MRI). PRESENTATION OF CASE: A 78-year-old man with a history of cerebral infarction was undergoing follow-up MRI every 6 months. This follow-up revealed a small abnormality in the left cerebellar hemisphere without clinical symptoms. Subsequent MRI showed lesion growth accompanying clinical symptoms. As cerebellar tumor was suspected, the lesion was extirpated. The histological diagnosis was anaplastic astrocytoma. Local recurrence developed and the patient died 20 months postoperatively. DISCUSSION: Cerebellar gliomas sometimes do not exhibit the common MRI findings of supratentorial gliomas, leading to difficulty with preoperative diagnosis. In this case, we initially diagnosed asymptomatic cerebellar infarction because the lesion was small and asymptomatic. The abnormal lesion gradually grew and clinical symptoms appeared. Cerebellar glioma may show few signs characteristic of tumor on MRI in the initial stages. CONCLUSION: When MRI detects a new, faint abnormality in the cerebellum, close follow-up of clinical symptoms and MRI on suspicion of glioma is warranted.