Intraventricular hydatid cyst causing entrapped temporal horn syndrome: Case report and review of literature.

Entrapped temporal horn is due to obstruction of one lateral ventricle in the region of trigone causing dilatation of the temporal horn. The isolated temporal horn presents itself as mass lesion. Intraventricular hydatid cyst presenting as an entrapped temporal horn has not been reported in literature till now. We report two cases of intraventricular hydatid cyst causing entrapped temporal horn.

INTRODUCTION

Entrapment of temporal horn is a rare entity. It is due to an obstruction of the trigone of the lateral ventricle which seals off the temporal horn from the rest of the ventricular system.[12] Continued secretion of cerebrospinal fluid by choroid plexus within the temporal horn leads to progressive dilatation of temporal horn and is presented as space occupying lesion. Intraventricular hydatid cyst is rarely reported in literature,[3] and it causing entrapped temporal horn had not been reported till date. We are reporting two cases of entrapped temporal horn due to hydatid cyst who presented as a space occupying lesion.

CASE REPORTS

Case 1

History

A 25- year old female was presented with complex partial seizure for three months. She had bifrontal headache for last two months which was moderate in intensity and aggravated in the early morning hours. Headache was often associated with vomiting, however vomiting did not relieve headache.

Examination

The patient was conscious and oriented with time, place, and person. There was no sensory or motor deficit. All cranial nerves were normal. There was bilateral early papilloedema. Enhanced computed tomography (CT) scan of head showed- left temporal cystic mass without any enhancing area with perifocal oedema. The cyst had attenuation value of 7 hounsefield unit [Figure 1].

Figure 1

Contrast-enhanced computed tomography scan of head (horizontal cut) showing left temporal cystic mass with perifocal oedema without any enhancing area (Case 1)

Surgery

Left temporal craniotomy was done. After corticectomy, the dilated left temporal horn was opened, which led the clear fluid to come out under pressure. There was a well defined whitish cyst of 2.5cm × 2 cm size present at trigone and was removed in without rupture [Figure 2].

Figure 2

Photograph of specimen showing spherical cyst of 2.5 cm × 2 cm whitish in color, floating in the test tube containing formaline (Case 1)

Case 2

A 8 year old girl child presented in casualty in drowsy state. She had complaints of generalized headache since last four months associated with gradual diminution in vision. There was no history of vomiting or any focal neurological deficit. She was receiving treatment with some private practitioner but was not relieved.

Clinical examination and evaluation

The patient was drowsy, and was not oriented with time place or person. There was no apparent cranial nerve palsy or any evidence of focal neurologic deficit. Bilateral papilledema was present. Magnetic resonance imaging showed trapped temporal and occipital horn of right lateral ventricle with marked perifocal edema with minimal subfalcine herniation [Figure 3].

Figure 3

FLAIR sequence - Magnetic resonance image (horizontal cuts) showing dilated right temporal and occipital horn with perifocal edema (Case 2)

Management

The patient underwent urgent right temporal craniotomy. The right occipital and temporal horns were found dilated. Cerebrospinal fluid came out with pressure. A well defined cystic mass lesion was found in the region of trigone. The cyst was marsupialized and obstruction due to the cyst relieved.

Histopathological examination

Microscopically, the typical laminated cyst wall could be seen and the compressed surrounding tissue showed mononuclear inflammatory cell infiltrates. Diagnosis of hydatid cyst was confirmed [Figure 4].

Figure 4

Microphotograph showing laminated wall of hydatid cyst (Hematoxyling and eosin stain, 100×)

Post operative course

Post operative period was uneventful. Follow- up showed complete recovery in headache and papilloedema. There was no evidence of other cyst on chest X-ray and ultrasound abdomen.

DISCUSSION

Hydrocephalus results when the flow of cerebrospinal fluid is impeded. When the block lies within the ventricular system, it is termed “obstructive hydrocephalus”. Both active secretion of cerebrospinal fluid by the choroid plexus and pulse waves from the plexus expand the trapped part of the ventricular system.[145] Brain parenchyma has only a limited capacity to absorb cerebrospinal fluid. If part of the ventricular system is closed off from the rest, and if the sealed off section contains choroid plexus, a partial or focal hydrocephalus may result. It may develop in two circumstances. First, obstruction of one foramen of monro may cause hydrocephalus confined to one ventricle.[16] This so-called unilateral hydrocephalus leads to symptoms of raised intracranial pressure. Unilateral obstruction of foramen of monro may be due to lesions such as colloid cyst of third ventricle, tumor of the septum pellucidum and thalamus, congenital gliotic atresia of foramen of Monro and after ventriculitis or surgical procedure within lateral ventricle.[6-9] Second condition where partial hydrocephalus may occur is after meningitis in infancy.[110]

Entrapment of temporal horn was first termed by Maurice-Williams, et al.[1] to describe a form of focal hydrocephalus. He described three cases of a syndrome in which obstruction of the trigone of the lateral ventricle seals off the temporal horn from the rest of the ventricular system. As temporal horn contains choroid plexus and cerebrospinal fluid secreted by these choroid plexus leads it to expand into a cyst. This gives rise to the symptoms of raised intracranial pressure as well as appropriate features of focal cerebral dysfunction such as a dysphasia or a contralateral hemiparesis.

Tsugane, et al[11] reported two cases of entrapment of temporal horn due to intraventricular block of cerebrospinal fluid flow as a consequence of choroid plexitis resulting in obstruction of the cerebrospinal fluid pathway at atrium. External drainage followed by shunt emplacement was done and the patient improved.

Watanabe Takao et al.[2] reviewed eight cases including one case, which was due to intraventricular hemorrhage caused by rupture of a large left parasplenial arteriovenous malformation. He successfully treated the case by ventriculoteritoneal shunt.

Intraventricular hydatid cyst is rarely reported. Evliyaoglu and Keskil[3] reported a case of a 7- year old girl who had a free floating, intraventricular hydatid cyst, diagnosed by CT examination inside the enlarged left lateral ventricle of an associated Dandy Walker malformation. The patient underwent surgery and the cyst was removed.

CONCLUSION

We report two a cases of entrapment of temporal horn due to hydatid cyst, which is not reported in literature till date. Entrapment of temporal horn due to hydatid cyst may be suspected in patients who develop symptoms of an expanding temporal lobe mass with or without a primary lesion particularly in endemic area and high index of suspicion is a must to diagnose it. Surgical excision without rupture of the cyst is the treatment of choice.