Colloid cyst

Case contributed by Ammar Ashraf


Positional headache and visual disturbance. Bilateral papilledema on ophthalmological evaluation.

Patient Data

Age: 40 years
Gender: Female

FINDINGS: A well-defined rounded nodular lesion measuring about 2.5 x 2.3 cm is sen in the roof of the third ventricle. The lesion is causing obstruction of the foramen of Monro, leading to mild dilatation of both lateral ventricles. The lesion is minimally hyperintense on T1W and mildly hypointense on T2 weighted images and shows mild peripheral ring-like enhancement. A few small mildly enhancing nodules which are hyperintense on T1W and hypointense on T2 are seen along its superior margin. The internal cerebral veins are seen stretched over the lesion. No obvious aneurysm is noted in the circle of Willis. A small well-defined mulberry like nodule measuring ~2 cm is seen in the soft tissues of the scalp in the vertex, which is likely a sebaceous cyst.

IMPRESSION: Well-defined lesion in the roof of the third ventricle with mild proximal hydrocephalus, which is likely a colloid cyst, however, small enhancing nodular lesions seen in the roof of the lesion are atypical imaging features of a colloid cyst.


FINDINGS: A well-defined rounded hyperdense lesion measuring 2.4 x 2.4 cm is seen within the roof of the third ventricle, which is likely a colloid cyst. Mildly dilated both lateral ventricles, likely due to obstruction at the level of the foramen of Monro. Two frontal VP shunts with their tips lying within the frontal horns of the lateral ventricles are seen in situ. No recent infarction or intracranial hemorrhage is seen.

CT brain three weeks after surgery


FINDINGS: Status post-frontal burr hole craniotomy. The previously noted colloid cyst at the level of the foramen of Monro has largely been surgically removed, leaving behind a small residual hypodensity. Mild bleed is seen in the lateral ventricles (likely post-surgical). Some hypodensities are seen in the right frontal lobe and left basal ganglia region which are likely post-surgical changes. A VP shunt is seen in place with its tip lying in the substance of the right frontal lobe.

Case Discussion

Procedure: Endoscopic aspiration and partial removal of the wall of the colloid cyst.

Diagnosis: Colloid cyst is histologically identified. No malignancy is seen.

Scalp cyst excision histopathology: Consistent with pilar/sebaceous cyst. Negative for malignancy.

How to use cases

You can use Radiopaedia cases in a variety of ways to help you learn and teach.

Creating your own cases is easy.

Updating… Please wait.

 Unable to process the form. Check for errors and try again.

 Thank you for updating your details.