J Neurosurg 75:960-962, 1991
Obstructive hydrocephalus caused by an abnormal vein in the aqueduct Case report AKIRA WATANABE, M.D., Rvo31 ISHI1, M.D., MASAKI KAMADA, M.D., YASUO SUZUKI, M.D., KAZUHIRO HIRANO, M.D., AND HIRONARI OKAMURA,M.D. Deparlment of Neurosurgeo,, Kawasaki Medical School Hospital, Kurashiki. Okayama, Japan v A case is reported of aqueductal stenosis caused by an abnormal draining vein and demonstrated by computerized tomography and magnetic resonance imaging. Placement of a ventriculoperitoneal shunt relieved the patient's progressiveheadaches. KEY WORDS
9
venous malformation
QUEDUCTAL stenosis may be caused by various conditions, including tumors, subarachnoid hemorrhage, and congenital or postinflammatory gliotic atresia. We report a rare case of aqueductal stenosis caused by an abnormal vein coursing through the aqueduct toward the quadrigeminal cistern.
A
Case Report
This 39-year-old man was admitted to our hospital with a 1-year history of headaches. The headaches progressively intensified, but were not accompanied by nausea or vomiting. Examination. Physical examination was normal. Neurological examination showed the patient to be alert and well-oriented, with a head circumference of 58.2 cm. There was no evidence of papilledema, optic atrophy, or sensorimotor abnormalities. Computerized tomography (CT) showed obstructive hydrocephalus and an abnormal contrast-enhanced lesion at the floor of the fourth ventricle near the aqueduct (Fig. 1), considered to be a venous structure crossing the aqueduct from the floor of the fourth ventricle toward the quadrigeminal cistern. Magnetic resonance (MR) imaging showed the lesion in the aqueduct and also revealed a vermicular lesion in the midbrain (Fig. 2). An axial T2weighted MR image (TR 2000 msec, TE 100 msec) showed high signal intensity referable to the vermicular lesion, which appeared to be a venous structure with a slow blood flow. 960
aqueductal stenosis
9
hydrocephalus
Operation. A ventriculoperitoneal shunt was placed, which caused relief of the patient's headaches. Postoperative CT showed resolution of the ventricular dilatation, but the vermicular lesion of the midbrain was clearly revealed (Fig. 3). There was no connection between the venous structure in the aqueduct and the venous structure within the parenchyma of the midbrain. The lesion that was demonstrated by CT and MR imaging was further confirmed by postoperative digital subtraction angiograms. Postoperative MR imaging clearly showed the abnormal draining vein, which penetrated the lowest part of the rectum mesencephali and obstructed the aqueduct (Fig. 4). Discussion
A wide variety of congenital and acquired factors are known to induce aqueductal stenosis; however, obstruction or stenosis of the aqueduct caused by vascular malformation is rare. 9 In the majority of such cases, the cause is either an arteriovenous malformation or a cavernous angioma. 35-s' ~-13Aqueductal stenosis caused by a vein or the venous elements of an angioma is, therefore, extremely rare. ~,~_,5 In the case reported here, an abnormal draining vein caused the aqueductal stenosis and induced obstructive hydrocephalus. This vein penetrated the tectum mesencephali and crossed through the aqueduct from the fourth ventricle toward the quadrigeminal cistern, where it drained into the precentral cerebellar vein. The Z Neurosurg. / Volume 75/December, 1991
Aqueductal stenosis caused by abnormal vein
FIG. 1. Preoperative computerized tomography scans with contrast enhancement. LdL Scan showing abnormal enhanced lesion in the fourth ventricle (arrowhead). Rtght: Scan showing obstructive hydrocephalus and the precentral cerebellar vein (arrow).
FI
Obstructive hydrocephalus caused by an abnormal vein in the aqueduct Case report AKIRA WATANABE, M.D., Rvo31 ISHI1, M.D., MASAKI KAMADA, M.D., YASUO SUZUKI, M.D., KAZUHIRO HIRANO, M.D., AND HIRONARI OKAMURA,M.D. Deparlment of Neurosurgeo,, Kawasaki Medical School Hospital, Kurashiki. Okayama, Japan v A case is reported of aqueductal stenosis caused by an abnormal draining vein and demonstrated by computerized tomography and magnetic resonance imaging. Placement of a ventriculoperitoneal shunt relieved the patient's progressiveheadaches. KEY WORDS
9
venous malformation
QUEDUCTAL stenosis may be caused by various conditions, including tumors, subarachnoid hemorrhage, and congenital or postinflammatory gliotic atresia. We report a rare case of aqueductal stenosis caused by an abnormal vein coursing through the aqueduct toward the quadrigeminal cistern.
A
Case Report
This 39-year-old man was admitted to our hospital with a 1-year history of headaches. The headaches progressively intensified, but were not accompanied by nausea or vomiting. Examination. Physical examination was normal. Neurological examination showed the patient to be alert and well-oriented, with a head circumference of 58.2 cm. There was no evidence of papilledema, optic atrophy, or sensorimotor abnormalities. Computerized tomography (CT) showed obstructive hydrocephalus and an abnormal contrast-enhanced lesion at the floor of the fourth ventricle near the aqueduct (Fig. 1), considered to be a venous structure crossing the aqueduct from the floor of the fourth ventricle toward the quadrigeminal cistern. Magnetic resonance (MR) imaging showed the lesion in the aqueduct and also revealed a vermicular lesion in the midbrain (Fig. 2). An axial T2weighted MR image (TR 2000 msec, TE 100 msec) showed high signal intensity referable to the vermicular lesion, which appeared to be a venous structure with a slow blood flow. 960
aqueductal stenosis
9
hydrocephalus
Operation. A ventriculoperitoneal shunt was placed, which caused relief of the patient's headaches. Postoperative CT showed resolution of the ventricular dilatation, but the vermicular lesion of the midbrain was clearly revealed (Fig. 3). There was no connection between the venous structure in the aqueduct and the venous structure within the parenchyma of the midbrain. The lesion that was demonstrated by CT and MR imaging was further confirmed by postoperative digital subtraction angiograms. Postoperative MR imaging clearly showed the abnormal draining vein, which penetrated the lowest part of the rectum mesencephali and obstructed the aqueduct (Fig. 4). Discussion
A wide variety of congenital and acquired factors are known to induce aqueductal stenosis; however, obstruction or stenosis of the aqueduct caused by vascular malformation is rare. 9 In the majority of such cases, the cause is either an arteriovenous malformation or a cavernous angioma. 35-s' ~-13Aqueductal stenosis caused by a vein or the venous elements of an angioma is, therefore, extremely rare. ~,~_,5 In the case reported here, an abnormal draining vein caused the aqueductal stenosis and induced obstructive hydrocephalus. This vein penetrated the tectum mesencephali and crossed through the aqueduct from the fourth ventricle toward the quadrigeminal cistern, where it drained into the precentral cerebellar vein. The Z Neurosurg. / Volume 75/December, 1991
Aqueductal stenosis caused by abnormal vein
FIG. 1. Preoperative computerized tomography scans with contrast enhancement. LdL Scan showing abnormal enhanced lesion in the fourth ventricle (arrowhead). Rtght: Scan showing obstructive hydrocephalus and the precentral cerebellar vein (arrow).
FI
