Episodic Tourette's syndrome in a patient with citrullinemia.

hancement at the operative site may simply represent recurrent tumor. We therefore provide clinical and radiographic follow-up data on patients in whom postoperative enhancement appeared along the line of resection (Table). Late CT scan observations when considered together with the clinical course suggest the following: (1) “benign” contrast enhancement can occur after brain tumor surgery; its appearance is delayed and it disappears spontaneously; and (2) when enhancement at the operative site persists for longer than 3 to 4 months, there is increasing concern that recurrent tumor is a contributing factor. Frequent postoperative CT scans were the “methods of procedure” by which we analyzed patterns of contrast enhancement in the postoperative brain. Dr Weisberg has confused our method with our conclusion. We recommend a single postoperative scan, but we also recommend that this scan be performed on the third or fourth postoperative day. Postoperative enhancement in brain tumor patients is more than a radiological curiosity. It can mimic residual enhancing tumor leading to inappropriate treatment decisions and misinterpretations of response to treatment 123.