Giant cavernous malformation of the occipital lobe.

A 15-year-old boy who developed severe headaches and an incomplete homonymous hemianopia was found to have a large, well-circumscribed, multilobulated intracranial mass in the contralateral occipital lobe. The initial impression was that of a low-grade glioma or a vascular malformation. When the lesion increased in size and complexity, concern arose about the possibility of a malignant glioma. Upon craniotomy, it proved to be a giant cerebral cavernous malformation. This case is remarkable in that most cavernous malformations do not become symptomatic before the third decade of life and rarely attain such a large size.