Colloid cyst causing a trapped ventricle

Case contributed by Dr Hamdy Mohammed Ibrahim


Elderly male with chronic headache, presented with acute projectile vomitings and gradual blurring of vision followed by reduced consciousness.

Patient Data

Age: 60 years
Gender: Male

Ovoid hyperdense lesion seen impacted within the anterior 3rd ventricle and its supraventricular recess.  It obstructs the foramen of Monro bilaterally causing supratentorial hydrocephalus. A VP shunt seen in the right lateral ventricle causing over drainage as it appears collapsed. The left lateral ventricle remains dilated and the septum pellucidum is displaced toward the right lateral ventricular lumen.

No transependymal edema, which favors incomplete obstruction.

Case Discussion

This case demonstrates the typical and pathognomonic appearances of a colloid cyst. As the cyst is close to the foramen of Monro and currently only one ventricle is being drained, it may need a second shunt tube or fenestration of the septum pellucidum to allow proper drainage of each lateral ventricle.

Endoscopic resection is the best way with the least complications; unfortunately, it is costly and needs expert neurosurgeons.

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