Acute and chronic subdural hygromas are common postoperative clinical complications of ventricular shunting, arachnoid cyst marsupialization and arachnoid cyst resection.1 This article introduces a case of subdural hygroma after resection of a space-occupying lesion in the left lateral ventricle that resulted in compressive brainstem deformation and reviewed the recent related literature. The conclusion is that in related surgical procedures, prevention of rapid cerebrospinal fluid loss and excessive fluctuations in intracranial pressure are especially important.