UMEM Educational Pearls

Question

Elderly male presents with headache, confusion, and trouble with gait. What's in your differential diagnosis?

Answer

Based on the CT scan shown, the differential here includes epidermoid and arachnoid cyst

Arachnoid cysts (AC) occur within the cerebrospinal axis and do not communicate with the ventricular system. Most occur in the middle cranial fossa and are typically benign; continuing cerebrospinal fluid

The majority of AC occurs from abnormalities in development, but a small portion occurs secondary to post-surgical adhesions or in association with cancer.

MRI is the test of choice to help define the extent of the cyst as well as determine alternative diagnoses.

Treatment is variable with some experts stating that only symptomatic ACs should be treated with others recommending removal to avoid future complications. 

The patient in the stem presented with symptoms secondary to complications from the AC.

References

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Table adapted from Radiology Review Manual, 7th edition, by Wolfgang Dähnert