Paradoxical clustering of brain metastases in an underperfused cerebral hemisphere.

OBJECTIVE To describe a patient with a predominantly unilateral intracranial arterial stenosis who then developed metastatic lung cancer to the brain, with the tumors preferentially depositing in the underperfused cerebral hemisphere. DESIGN Case report. SETTING Inpatient neurology ward at a university medical center. Patient A 68-year-old woman with intracerebral arterial stenosis who then developed lung cancer with multiple metastases to the brain in an asymmetric arrangement. Main Outcome Measure The location of metastatic tumor deposits in relation to intracerebral arterial stenosis in the cerebral hemispheres of our patient. RESULTS In this patient, most of the metastatic tumors were located in the underperfused cerebral hemisphere. CONCLUSIONS This case demonstrates the concept that emboli washout by vigorous circulation is more important than direct delivery of embolic material in determining whether tumor cells will implant and grow in the brain.