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Arachnoid granulation

Case contributed by Mostafa Elfeky
Diagnosis almost certain

Presentation

Headache.

Patient Data

Age: 50 years
Gender: Female
ct

Normal brain CT study.

A globular hypodense area is noted inside the right sigmoid sinus with surrounding normal homogeneous density of the dural sinus. It shows overlying bone scalloping. No signs of intracranial hypertension. Features are suggestive of arachnoid granulation.

The choroid plexus in the posterior horn of both lateral ventricles are mildly enlarged with displaced choroid calcifications peripherally, suggestive of choroid plexus xanthogranulomata.

Case Discussion

Typical features and location of incidental arachnoid granulation. It is a projection of the arachnoid membrane inside dural sinus with density similar to SCF.

Choroid plexus xanthogranulomata are also incidental finding and are hardly to be differentiated from normal choroid plexus. Suggestive CT features are enlarged choroid plexus with peripherally displaced calcifications.

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