Middle cranial fossa arachnoid cyst and subdural hygroma

Case contributed by Bahman Rasuli
Diagnosis certain


New onset headache and disequilibrium

Patient Data

Age: 25 years
Gender: Female

There is a 6 x 8 x 10 cm large extra-axial fluid signal arachnoid cyst at the left frontotemporal region causing marked pressure on adjacent brain parenchyma and effacement of adjacent gyri as well as midline shift measuring about 1 cm to the right side. Subdural hygroma adjacent to the left cerebral hemisphere measuring about 3 cm thickness is also seen in keeping with a ruptured arachnoid cyst.

Case Discussion

Most arachnoid cysts are asymptomatic throughout life. Symptoms are produced when arachnoid cysts are large or complicated by subdural hygroma or intracystic hemorrhage.

It is worth noting that small cysts, because they constrain CSF, prevent it from flowing with cardiac pulsations, are therefore usually brighter than "normal" CSF. Large cysts, however, like this one can have turbulent flow within them as they are deformed during systole and thus have volume loss.

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.