cavernous hemangioma constitutes 5 - 10% of vascular malformations occurring in the entire central nervous system ( cns ) .
intraventricular location constituting 2.5 - 10.8% of cerebral cavernous hemangioma is uncommon because most of them are usually found in the parenchyme of cns4 ) .
so far , the intraventricular cavernous hemangioma has been reported to be less than 90 cases to our best knowledge .
those located in the third ventricle account for approximately half of all intraventricular cavernous hemangiomas .
in particular , cavernoma at the foramen of monro which have been reported to be about 13 cases are very rare and may be difficult to differentiate from other brain tumors1,4 ) . herein , we present an additional case of cavernous hemangioma located in the foramen of monro of the third ventricle and review the relevant literatures .
a 30-year - old female patient who was pregnant presented with intermittent non - throbbing headache for a month before admission .
she complained the projectile vomiting and fever without consciousness disturbance which were observed shortly after normal vaginal delivery .
she was referred to department of neurology under the impression of meningitis . on physical examinations ,
computed tomogram ( ct ) showed enlargement of both lateral ventricles which may be caused by 3 cm sized multi - lobular calcified mass with slightly peripheral rim enhancement at the foramen of monro in the third ventricle .
magnetic resonance image ( mri ) revealed a relatively well - delineated mass at the foramen of monro with heterogeneous signal intensity on both t1 and t2 weighted images .
the surrounding rim of low signal intensity around mass was not delineated definitely on t2-weighted image .
a peri - lesional edema in the left thalamus was observed on the flair image and only minimal peripheral rim enhancement around mass was found on enhanced t1-weighted image ( fig .
operative findings showed that the mass with xanthochromic and lobular surface obstructing the foramen of monro was located in the third ventricle .
the left posterior margin of the mass was close contact to the thalamus while resection .
immunostaining for smooth muscle actin ( sma ) was positive in the vessel wall ( fig .
after operation , the patient 's symptoms including vomiting and headache were recovered gradually ( fig .
cavernous hemangiomas known as cavernous malformations , cavernous angiomas or cavernomas are a kind of vascular malformation which is angiographically occult unlike arteriovenous malformations .
these benign lesions are composed of sinusoidal vascular channels which are lined with a single layer endothelium predisposing to hemorrhage and have perilesional surrounding gliosis2 ) .
hemorrhages at different stages due to repeated bleeding , occlusion and thrombosis in the vascular channels are found within the lesion .
progressive pseudotumorous evolutions are induced by repeated bleeding which occur in the immediate vicinity of cavernous hemangioma , leading to hemosiderin deposits and gliosis2 ) .
most of them occur in the intra - axial and supratentorial regions and they are typically located in the subcortical deep white matters , basal ganglia , brain stem and cerebellum .
however , they have rarely seen in the intraventricular or extra - axial locations4 ) .
kivelev et al.4 ) summarized intraventricular cavernomas of 89 cases including their own cases and reported that 34 cases ( 38% ) of them were located in the third ventricle .
third ventricular cavernomas can be classified into suprachiasmatic , foramen of monro , lateral wall , and floor regions depending on the location3 ) .
those located at the foramen of monro may have particular clinical interests because of hydrocephalus due to foraminal obstruction and have been reported to be only 13 cases so far1,4,5 ) .
it is notable that our case can be additional one as foramen of monro cavernomas of third ventricle .
clinical symptoms of intraventricular cavernomas may be elicited by mass and increased intracranial hypertension due to acute bleeding or obstruction of cerebrospinal fluid pathway . in our case ,
headache and vomiting resulted from increased intracranial pressure due to obstructive hydrocephalus induced by cavernoma located at the foramen of monro .
fourteen intraventricular cavernomas located at the foramen of monro including our case are summarized in the table 1 .
there were 5 males and 9 females whose age distribution is ranged from 11 years to 64 years .
the clinical findings were symptoms associated with hydrocephalus in most cases , hemorrhages in 3 cases , focal neurological deficits in 5 cases . in all patients ,
surgical removal was performed completely without significant neurological deficits using the microsurgery or / and endoscopic surgery through the trans - callosal or trans - cortical approaches .
most of them often showed calcification on computed tomogram ( ct ) and heterogenous signal intensities and mild enhancement on magnetic resonance image ( mri ) .
typical ct findings of cavernous hemangiomas in the third ventricle show moderately hyper - dense lobular lesions with mild contrast enhancement . unlike arteriovenous malformations
, they are angiographically occult because cavernous hemangiomas usually do not have feeding or draining vessels obviously .
therefore , mri has been useful in diagnosis of clinically silent and angiographically occult cavernomas .
common mri features include a hyper to iso - intense center correlated to the hemorrhages at different stage on t1-weighted images and a surrounding hemosiderin rim of low intensity caused by calcification or fibrosis on t2-weighted images .
also , it has been reported that typical perilesional hemosiderotic rim might be thinner or absent and core of lesion could be less heterogenous in the intraventricular cavernomas compared with intraparenchymal cavernomas4 ) .
our case showing heterogenous signal intensities in the center of lesion and unclear hemosiderin rim might be confused with other brain tumor lesions .
it is considered that additional gradient echo sequences which can detect the hemorrhages in different stages can help differentiate from hemorrhagic form of cavernous hemangioma .
anaplastic astrocytomas , glioblastomas and oligodendrogliomas showing heterogeneous signals on mri may mimic cavernous hemangiomas because of intratumoral necrosis , hemorrhage or calcification . however , tumor is usually non - hemorrhagic and surrounded by prominent perilesional edema .
cystic and hemorrhagic metastases , which may occur with melanoma , adenocarcinoma has multiple lesions .
furthermore , the third ventricle is a very uncommon site for metastasis or other primary brain tumors .
colloid cysts and germinoma may occur at this location but can be excluded by their different appearance on mri .
compared with usual radiological findings of cavernomas , our case was not considered as typical cavernoma with peripheral hemosiderin rim and heterogenous internal signal intensities despite normal cerebral angiogram initially . therefore , vascular lesions such as arteriovenous malformation , venous angioma , tumorous lesions such as glioma , central neurocytoma , subependymal giant cell astrocytoma , colloid cyst , craniopharyngioma , metastasis , meningioma , teratoma , germinoma should be differentiated through full sequences of mri , angiogram , biopsy and microsurgery4 ) .
in our case , this lesion was initially interpretated as tumor such as central neurocytoma , but confirmed as cavernoma through the microsurgery . with regard to the management of cavernous hemangiomas , only a few reports suggested the effectiveness of radiotherapy .
however , proliferation and recurrence have been described in several cases treated conservatively or with radiotherapy alone .
therefore , surgical treatment is considered curative if they are readily accessible although management in asymptomatic patients remains controversial .
we present a very rare case of intraventricular cavernous hemangioma located at the foramen of monro that may mimic tumor lesions .
 intraventricular cavernous hemangiomas are uncommon . among them , those occurred at the foramen of monro in the third ventricle may be of particular interest because of its rarity , development of hydrocephalus , being differentiated from other brain lesions . 
 we present a rare case of intraventricular cavernous hemangioma at foramen of monro which was resected through microsurgery and also review the relevant literatures . 
INTRODUCTION
CASE REPORT
DISCUSSION
CONCLUSION