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Hydatid cyst of the aquaduct of Sylvius
Hydatid cyst of the aquaduct of Sylvius Case report
Hamit Z. G6kalp and Ahmet Erdo~an.
Case report Summary A 17-year-old female entered the hospital on December 19, 1983 with complaints of headache, nausea, vomiting and difficulty in walking. Two weeks before admission she began to have periodic 'pressure pain' which frequently was sharp and often more severe at night, interfering with her sleep. One week before entry her pains increased in frequency and severity and were associated with nausea and vomiting. Two days before admission she began to complain of blurred vision and difficulty in walking due to sensation of inbalance. Her family were sheep farmers and they owned 4 shepherd dogs. On examination her physical examination proved to be within normal limits. Neurological examination revealed bilateral 4 diopter papilledema with flame shaped retinal hemorrhages. Bilateral slight weakness of lateral gaze with a transient coarse horizontal nystagmus appearing on extreme lateral gaze was present. There was no spontaneous nystagmus. Though there were no cerebellar signs, her gait was slightly broadbased and somewhat unsteady. Plain skull and chest X rays were normal. A brain scan revealed no pathology either. CT showed enlarged lateral and third ventricles. A round homogenous, hypodense area with regular contour, having attenuation values
In countries where hydatid disease is prevalent, cerebral hydatid cyst may be responsible for as much as 10% of all intracranial expansive processes ~. These cysts may be localized in various anatomical sites within the calvarium as well as the skull itselfTM.The authors present a hydatid cyst that was localized in the proximal third of the aquaduct of Sylvius producing increased intracranial pressure by obliteration of the aquaduct. Preoperative diagnosis was made by computerized tomography and the cyst was removed by a posterior fossa approach. Key words: Aquaduct of Sylvius, cerebral hydatid cyst, hydrocephalus.
of spinal fluid was seen at the upper third aquaductal level. With intravenous contrast injection this hypodense area showed 2-4 H U increase in attenuation values. The fourth ventricle was within normal limits (Fig. 1). On December 23, 1983 the patient was operated. Surgical intervention was performed through a midline suboccipital craniectomy. Tonsils were elevated and the floor of the fourth ventricle, calamus scriptoius and cisterna magna was protected with cottonoids. The vermis was split about 3 cm at its lower border and retracted laterally. At the upper part of the fourth ventricle there was a cyst membrane
Ankara University, lbni Sina Medical Center, Neurosurgery Dept. Sthhiye, Ankara, Turkey. Address for correspondence and reprint requests: Hamit Z. GOkalp, Ankara Oniversitesi, lbni Sina Hastanesi, NOro~iriirjiABD., Slhhiye, Ankara, Turkey. Accepted 3.9.87 Clin Neurol Neurosurg 1988. Vol.90-1.
83
Fig. 1. Preoperative CT scan. The dilatation of the proximal aquaduct. A round contoured cystic mass, behind the third ventricle.
bulging out through the aquaduct (Fig. 2a and b). Aquaduct was distended and obstructed by the cyst. The cyst wall was not attached to the neural tissue. Because the cyst was large and distended to the aquaduct internally, no attempt was made to remove it with hydrostatic expulsion. Instead the cyst was entered with a fine needle and aspirated with an injector. After aspiration the cyst became slack and the cyst membrane was easily pulled out with a forceps, without exerting any traction. Before puncturing the cyst, the operative field was covered with cottonoids and generously washed with 3% hypertonic salin solution. Postoperative course was uneventful. All symptoms subsided in the first postoperative day and completely disappeared within five days. She was discharged on the ninth day of her operation. Pathological examination showed it to be a hydatid cyst. On January 16, 1984 the patient was readmitted for radiotherapy and received 1000 R to her posterior fossa and spinal axis in 7 sessions. CT on August 14, 1984 was within normal limits. At her last control on February 1985 she was found to be in excellent condition and had no complaints.
Fig. 2a and b. The exposed fourth ventricle after splitting the vermis. The cyst is bulging into the fourth ventricle through the aquaduct. a. The photograph of the operative area. b. The sketch of the same photograph (r: Retractor, v: Vermis, VI: Fourth ventricle, c: cyst).
84
Fig. 3. Postoperative CT after two years,
done with caution in the region where hydatid disease is endemic because of the possibility to enter the cyst cavity. During surgery prevention of the spillage of the content of the cyst over the exposed brain tissue is very important. This may cause recurrence with multiple cyst and a very severe allergic reaction. Generally hydatid cysts are easily removed by hydrostatic expulsion by squirting fluid around and under the cyst. In our case we could not perform this, in fear of traumatizing the periaquaductal structure. If a cyst is too large to remove without rupture, the cyst content may be sterilized by injecting formalin, hydrogen peroxide or 3% hypertonic saline. After five minutes the cyst content is aspirated through a small puncture, whereupon the cyst membrane can be removed totally. In case of spillage of the cyst fluid, irrigation of the operative field gives some protection but not for sure. A low dose of radiotherapy might still be necessary. In our case after three years there are no symptoms or signs that indicate recurrence.
Discus~on References
To our knowledge this is the first report of a hydatid cyst localized in the aquaduct of Sylvius. CT characteristics of its postcontrast enhancement, and - if there is - intracystal calcification differentiates it from an arachnoid cyst.l'5,6. CT is the best diagnostic tool for this type of lesions. Angiography is probably not helpful for a lesion of this size and on this site. Radioactive scanning may be helpful in a hemispheric large cyst demonstrating decreased activity, but it was normal in our case. Ventriculography should be
1 2 3 4 5 6
nANZAR, a'Onm~ S, JaMOVSSI M, et al. Intracranial and orbital hydatid cyst. Neuroradiol 1982; 22:211-4. INIGUEZ AR, JULIAN SJ. Hydatid cyst o f t h e b r a i n . J N e u rosurg 1955; 12:323-35. DHARKER SR, DHARLES RS, VAISHYA ND, el al. Cerebral hydatid cyst in central India. Surg Neurol 1977; 8:31-4. 0ZGEN T, BERTAN V, KANSU T, et al. I n t r a s e l l a r hydatid cyst. Case report. J Neurosurg 1984; 60:647-8. ABBASION K, RAHMAT H, AMELI N, et al. C T s c a n i n hydatid cyst. J Neurosurg 1978; 49:400-6. OZGEN T, ERBENGI A, BERTAN V, et al. The use of Computerized Tomography in the diagnosis of cerebral hydatid cyst. J Neurosurg 1979; 50:339-42.
85
Hamit Z. G6kalp and Ahmet Erdo~an.
Case report Summary A 17-year-old female entered the hospital on December 19, 1983 with complaints of headache, nausea, vomiting and difficulty in walking. Two weeks before admission she began to have periodic 'pressure pain' which frequently was sharp and often more severe at night, interfering with her sleep. One week before entry her pains increased in frequency and severity and were associated with nausea and vomiting. Two days before admission she began to complain of blurred vision and difficulty in walking due to sensation of inbalance. Her family were sheep farmers and they owned 4 shepherd dogs. On examination her physical examination proved to be within normal limits. Neurological examination revealed bilateral 4 diopter papilledema with flame shaped retinal hemorrhages. Bilateral slight weakness of lateral gaze with a transient coarse horizontal nystagmus appearing on extreme lateral gaze was present. There was no spontaneous nystagmus. Though there were no cerebellar signs, her gait was slightly broadbased and somewhat unsteady. Plain skull and chest X rays were normal. A brain scan revealed no pathology either. CT showed enlarged lateral and third ventricles. A round homogenous, hypodense area with regular contour, having attenuation values
In countries where hydatid disease is prevalent, cerebral hydatid cyst may be responsible for as much as 10% of all intracranial expansive processes ~. These cysts may be localized in various anatomical sites within the calvarium as well as the skull itselfTM.The authors present a hydatid cyst that was localized in the proximal third of the aquaduct of Sylvius producing increased intracranial pressure by obliteration of the aquaduct. Preoperative diagnosis was made by computerized tomography and the cyst was removed by a posterior fossa approach. Key words: Aquaduct of Sylvius, cerebral hydatid cyst, hydrocephalus.
of spinal fluid was seen at the upper third aquaductal level. With intravenous contrast injection this hypodense area showed 2-4 H U increase in attenuation values. The fourth ventricle was within normal limits (Fig. 1). On December 23, 1983 the patient was operated. Surgical intervention was performed through a midline suboccipital craniectomy. Tonsils were elevated and the floor of the fourth ventricle, calamus scriptoius and cisterna magna was protected with cottonoids. The vermis was split about 3 cm at its lower border and retracted laterally. At the upper part of the fourth ventricle there was a cyst membrane
Ankara University, lbni Sina Medical Center, Neurosurgery Dept. Sthhiye, Ankara, Turkey. Address for correspondence and reprint requests: Hamit Z. GOkalp, Ankara Oniversitesi, lbni Sina Hastanesi, NOro~iriirjiABD., Slhhiye, Ankara, Turkey. Accepted 3.9.87 Clin Neurol Neurosurg 1988. Vol.90-1.
83
Fig. 1. Preoperative CT scan. The dilatation of the proximal aquaduct. A round contoured cystic mass, behind the third ventricle.
bulging out through the aquaduct (Fig. 2a and b). Aquaduct was distended and obstructed by the cyst. The cyst wall was not attached to the neural tissue. Because the cyst was large and distended to the aquaduct internally, no attempt was made to remove it with hydrostatic expulsion. Instead the cyst was entered with a fine needle and aspirated with an injector. After aspiration the cyst became slack and the cyst membrane was easily pulled out with a forceps, without exerting any traction. Before puncturing the cyst, the operative field was covered with cottonoids and generously washed with 3% hypertonic salin solution. Postoperative course was uneventful. All symptoms subsided in the first postoperative day and completely disappeared within five days. She was discharged on the ninth day of her operation. Pathological examination showed it to be a hydatid cyst. On January 16, 1984 the patient was readmitted for radiotherapy and received 1000 R to her posterior fossa and spinal axis in 7 sessions. CT on August 14, 1984 was within normal limits. At her last control on February 1985 she was found to be in excellent condition and had no complaints.
Fig. 2a and b. The exposed fourth ventricle after splitting the vermis. The cyst is bulging into the fourth ventricle through the aquaduct. a. The photograph of the operative area. b. The sketch of the same photograph (r: Retractor, v: Vermis, VI: Fourth ventricle, c: cyst).
84
Fig. 3. Postoperative CT after two years,
done with caution in the region where hydatid disease is endemic because of the possibility to enter the cyst cavity. During surgery prevention of the spillage of the content of the cyst over the exposed brain tissue is very important. This may cause recurrence with multiple cyst and a very severe allergic reaction. Generally hydatid cysts are easily removed by hydrostatic expulsion by squirting fluid around and under the cyst. In our case we could not perform this, in fear of traumatizing the periaquaductal structure. If a cyst is too large to remove without rupture, the cyst content may be sterilized by injecting formalin, hydrogen peroxide or 3% hypertonic saline. After five minutes the cyst content is aspirated through a small puncture, whereupon the cyst membrane can be removed totally. In case of spillage of the cyst fluid, irrigation of the operative field gives some protection but not for sure. A low dose of radiotherapy might still be necessary. In our case after three years there are no symptoms or signs that indicate recurrence.
Discus~on References
To our knowledge this is the first report of a hydatid cyst localized in the aquaduct of Sylvius. CT characteristics of its postcontrast enhancement, and - if there is - intracystal calcification differentiates it from an arachnoid cyst.l'5,6. CT is the best diagnostic tool for this type of lesions. Angiography is probably not helpful for a lesion of this size and on this site. Radioactive scanning may be helpful in a hemispheric large cyst demonstrating decreased activity, but it was normal in our case. Ventriculography should be
1 2 3 4 5 6
nANZAR, a'Onm~ S, JaMOVSSI M, et al. Intracranial and orbital hydatid cyst. Neuroradiol 1982; 22:211-4. INIGUEZ AR, JULIAN SJ. Hydatid cyst o f t h e b r a i n . J N e u rosurg 1955; 12:323-35. DHARKER SR, DHARLES RS, VAISHYA ND, el al. Cerebral hydatid cyst in central India. Surg Neurol 1977; 8:31-4. 0ZGEN T, BERTAN V, KANSU T, et al. I n t r a s e l l a r hydatid cyst. Case report. J Neurosurg 1984; 60:647-8. ABBASION K, RAHMAT H, AMELI N, et al. C T s c a n i n hydatid cyst. J Neurosurg 1978; 49:400-6. OZGEN T, ERBENGI A, BERTAN V, et al. The use of Computerized Tomography in the diagnosis of cerebral hydatid cyst. J Neurosurg 1979; 50:339-42.
85