Enhancing meningeal blood vessels masquerading as leptomeningeal spread of tumor in obstructive hydrocephalus.

MR showed an enhancing mass in the pineal region and hydrocephalus and leptomeningeal enhancement, thought to indicate pinealoblastoma with leptomeningeal spread. During resection there was no evidence of spread, and repeat MR showed no residual tumor or meningeal enhancement, so the patient was not treated for metastasis. Because there were no signs of leptomeningeal tumor 4 months after surgery, the meningeal enhancement is thought to have been related to venous stasis secondary to obstructive hydrocephalus.