Kyste épidermoïde extradural géant

We here report the case of a 68-year old female patient presenting with a 6-month history of headaches and difficulty walking with cerebellar syndrome and balance disorders. Brain CT scan showed voluminous extradural median lesion in the Posterior Cranial Fossa (PCF) with calcifications, erosion in the occipital bone and peripheral contrast enhancement. MRI for characterizing lesions showed lesion extradural median process of PCF with hyposignal T1 (A), hypersignal T2 (B), Flair heterogeneous signal (C) with moderate peripheric enhancement (D) and diffuse hypersignal. Surgical treatment allowed complete tumor resection and histological examination confirmed the diagnosis of epidermoid cyst. Epidermoid cysts of the PCF are rare, they are slow-growing congenital tumors but they can occur at any age, without sex predominance. The most common intradural lesions occur at the level of the cerebellopontine and parasellar angle. CT scan shows well-defined tumor process without contrast enhancement. MRI allows for better characterization of the lesion as in our case. Differential diagnosis is made with arachnoid and dermoid cysts. Treatment of epidermoid cysts is based on surgery with complete removal of the tumor and the capsule.