Arachnoid cyst: extremely large

Case contributed by Yaïr Glick
Diagnosis certain

Presentation

Headache. Recurrent bouts of sinusitis. Suspected acute sinusitis.

Patient Data

Age: 16 years
This study is a stack
Axial bone
window
This study is a stack
Coronal
bone window
Download
Info

Complete opacification of sphenoid sinus on left, mucosal thickening on right. Tiny focal polypoid muosal thickening in floor of left maxillary sinus.
Adenoidal hypertrophy with moderate narrowing of nasopharynx and pharyngeal tonsillar hypertrophy with severe narrowing of oropharynx (not shown in entirety).
Thickened nasal conchae, left concha bullosa.

Large fluid-density right frontotemporal structure, probably a huge arachnoid cyst.

NB: The study was uploaded with a higher contrast than the original "sinus" (i.e. "internal acoustic canal") window to better display the intracranial structure.

This study is a stack
Axial
T1
This study is a stack
Axial
T2
This study is a stack
Axial
FLAIR
This study is a stack
Axial
T1 C+
This study is a stack
Axial
DWI
This study is a stack
Axial
ADC
This study is a stack
Axial
SWI
This study is a stack
Coronal
STIR
This study is a stack
Coronal
T1 C+
This study is a stack
Sagittal
T2
This study is a stack
Sagittal
T1 C+
Download
Info

Huge right frontotemporal arachnoid cyst causing a mass effect very mild for its size, including narrowing of the right lateral ventricle and a relatively mild subfalcine herniation.

Case Discussion

Incidentally discovered arachnoid cyst on CT sinuses.

The window for CT sinuses is very wide, rendering brain parenchyma and fluid an almost identical medium gray but nevertheless, the radiologist noticed an ever so slightly hypodense intracranial area on the right. Owing to its sharp borders, arachnoid cyst was the most likely candidate, and this was indeed proved by MRI.

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.