Hematoma of the quadrigeminal plate. Case report.

The authors report a case in which a hematoma of the quadrigeminal plate resulted from the rupture of a "cryptic" arteriovascular malformation (AVM) fed by the artery of the quadrigeminal plate. The AVM was symptomatic before rupturing and this clinical feature, associated with the lack of angiographic demonstration, led to the erroneous preoperative diagnosis of a tumor. In retrospect, the only finding that might have suggested the correct diagnosis was the beaded appearance on the ventriculogram of the aqueduct due to blood clots into this fluid space.