Arachnoid cysts are extra-axial non-neoplastic, cystic lesions, filled with CSF, lined with arachnoid membranes ^1-3. It is a common incidental discovery on neuroimaging in all age groups, and are more common asymptomatic and usually do not require surgery ^2,4. Symptoms and signs of arachnoid cysts depend on their size and location ³.

Quadrigeminal cistern arachnoid cysts occur between the collicular plates and the incisura notch of the tentorium. The symptomatology of quadrigeminal arachnoid cysts vary according to their size and depends on the severity of the compression on the tectal plate, brain stem, cerebellum, and aqueduct ³. Small cysts have a long-standing benign course and are usually asymptomatic ³.

This case describes the typical features of a small quadrigeminal cistern arachnoid cyst, which has a benign course, requiring observational and follow up.

Case courtesy

• Erick Cavalcante, MD - PGY-3, Radiology Resident, Department of Radiology
• Antonio Rodrigues de Aguiar Neto, MD - Radiologist, Department of Radiology
• Hospital da Restauração – Recife, PE – Brazil