Intracranial temporal cyst

Clinical History

A 43-year-old man reported chronic headaches for 5 years and an uninvestigated seizure 6 months ago. Neurological examination was normal.

Imaging Findings

MRI imaging detected a right temporal cystic lesion with geographical contours, hypointense at T1WI, heterogeneous at T2 flair, hyperintense at T2WI and diffusion (B1000).

Discussion

Epidermoid cyst is a rare benign dysembryoplastic lesion derived from ectodermal tissue, representing 0.3 to 1.8% of all primary brain tumours. [1]
Despite its congenital aetiology, the mean age of diagnosis is the 2nd and 4th decade, the most common location of epidermoid cyst being the cerebellopontine angle (37%) and parasellar region (30%). [2]
It may be asymptomatic and discovered incidentally, symptoms depend mainly on the location of the tumour, including seizures, vision difficulties, fever, neck stiffness, numbness, or weakness. However, headaches are the most common symptom.
Imaging appearance is relatively typical, CT shows a well-defined hypoattenuating extraaxial mass, with density similar to that of cerebrospinal fluid; rarely it is hyperdense due to calcification, haemorrhage, or high protein content.
MRI findings are reliable for the diagnosis. Epidermoid cysts are isointense to cerebrospinal fluid on T1-weighted and T2-weighted images, mixed signal on FLAIR images, restricted on diffusion (DWI), and usually do not enhance with gadolinium. [3]
The primary differential diagnosis is arachnoid cyst, it follows cerebrospinal fluid on all sequences including Flair and DWI, which help to distinguish them from epidermoid cysts.
It includes also dermoid cyst and cystic neoplasm. [4]

Differential Diagnosis List

Final Diagnosis

Epidermoid cyst

URL:	https://www.eurorad.org/case/12562
DOI:	10.1594/EURORAD/CASE.12562
ISSN:	1563-4086