Answer for BIR CoW 14 Jun 2026
Intraventricular NCC
Findings
Evidence of well defined T1 hypointense, T2 hyperintense cystic lesion with internal FLAIR isointense round component noted within the temporal horn of left lateral ventricle showing no diffusion restriction and eccentric foci of gradient blooming. On contrast administration, the lesion shows eccentric enhancing mural nodule representing the scolex. The lesion measures~ 2.1 (anteroposterior) x 1.8 (transverse) x 1.8 (cranio caudal) cm. Periventricular FLAIR Hyperintensity noted surrounding the left lateral ventricle.
Discussion
Intraventricular neurocysticercosis is a form of extraparenchymal NCC where cysticerci are located within the ventricular system, most commonly the fourth ventricle, followed by the lateral and third ventricles. It accounts for a small proportion of NCC cases but is clinically important due to the risk of obstructive hydrocephalus. The cyst is usually isointense or hypointense to CSF on Conventional MRI, making it difficult to detect on routine sequences. The scolex, a key diagnostic feature, may be seen as an eccentric mural nodule within the cyst. 3D-CISS (constructive interference in steady state) and FIESTA sequences are highly sensitive for demonstrating intraventricular cysts because of high contrast between cyst wall and CSF. MRI may show a thin-walled cystic lesion following CSF signal intensity with minimal or no surrounding edema. Ventricular dilatation with transependymal CSF seepage may be present due to obstruction of CSF pathways. Intraventricular cysts can cause Bruns syndrome, characterized by episodic headache, vertigo, and vomiting due to intermittent CSF obstruction. CT has limited sensitivity because the cyst fluid is similar in density to CSF; however, it may demonstrate hydrocephalus and ventricular asymmetry. Post-contrast enhancement is usually absent but may occur with inflammatory response or degenerating cysts. MR imaging may show signs of ventriculitis, including ependymal enhancement and debris within the ventricles. Differential diagnoses include arachnoid cyst, ependymal cyst, choroid plexus cyst, intraventricular tumors (ependymoma, central neurocytoma), and hydatid cyst. Endoscopic evaluation and removal are often considered for symptomatic intraventricular cysts causing hydrocephalus. MRI with high-resolution heavily T2-weighted sequences is considered the imaging modality of choice for detection and characterization. Recognition of intraventricular NCC is essential because it is a treatable cause of hydrocephalus and may be missed on routine brain imaging
Findings
Evidence of well defined T1 hypointense, T2 hyperintense cystic lesion with internal FLAIR isointense round component noted within the temporal horn of left lateral ventricle showing no diffusion restriction and eccentric foci of gradient blooming. On contrast administration, the lesion shows eccentric enhancing mural nodule representing the scolex. The lesion measures~ 2.1 (anteroposterior) x 1.8 (transverse) x 1.8 (cranio caudal) cm. Periventricular FLAIR Hyperintensity noted surrounding the left lateral ventricle.
Discussion
Intraventricular neurocysticercosis is a form of extraparenchymal NCC where cysticerci are located within the ventricular system, most commonly the fourth ventricle, followed by the lateral and third ventricles. It accounts for a small proportion of NCC cases but is clinically important due to the risk of obstructive hydrocephalus. The cyst is usually isointense or hypointense to CSF on Conventional MRI, making it difficult to detect on routine sequences. The scolex, a key diagnostic feature, may be seen as an eccentric mural nodule within the cyst. 3D-CISS (constructive interference in steady state) and FIESTA sequences are highly sensitive for demonstrating intraventricular cysts because of high contrast between cyst wall and CSF. MRI may show a thin-walled cystic lesion following CSF signal intensity with minimal or no surrounding edema. Ventricular dilatation with transependymal CSF seepage may be present due to obstruction of CSF pathways. Intraventricular cysts can cause Bruns syndrome, characterized by episodic headache, vertigo, and vomiting due to intermittent CSF obstruction. CT has limited sensitivity because the cyst fluid is similar in density to CSF; however, it may demonstrate hydrocephalus and ventricular asymmetry. Post-contrast enhancement is usually absent but may occur with inflammatory response or degenerating cysts. MR imaging may show signs of ventriculitis, including ependymal enhancement and debris within the ventricles. Differential diagnoses include arachnoid cyst, ependymal cyst, choroid plexus cyst, intraventricular tumors (ependymoma, central neurocytoma), and hydatid cyst. Endoscopic evaluation and removal are often considered for symptomatic intraventricular cysts causing hydrocephalus. MRI with high-resolution heavily T2-weighted sequences is considered the imaging modality of choice for detection and characterization. Recognition of intraventricular NCC is essential because it is a treatable cause of hydrocephalus and may be missed on routine brain imaging
Note:
We do not discourage differential diagnosis. But all the differentials must satisfy the findings noted in the case.
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Did you Know?
The order in which the names appear in this winner's list is based on the time of submission. The first person to send the correct answer gets his/her name on top of the list!
We do not discourage differential diagnosis. But all the differentials must satisfy the findings noted in the case.
If you feel you have answered rightly but cannot find your name in the above list, please call 09551942599.
Did you Know?
The order in which the names appear in this winner's list is based on the time of submission. The first person to send the correct answer gets his/her name on top of the list!