RESUMO
BACKGROUND: The traumatic complication of an arachnoid cyst (AC) with intracystic and subdural hematoma has been reported in many cases. However, a unilateral extradural hematoma (EDH) as a complication of AC is extremely rare. Most arachnoid cysts are unilateral and are located in the middle cranial fossa. Bilateral temporal AC alone is an extremely rare condition, and a bilateral EDH on top of a bilateral temporal AC has never been reported in the literature, to our knowledge. CASE DESCRIPTION: We report the case of a 25-year-old man with a known bilateral AC who was involved in a motor vehicle accident and developed a bilateral temporal EDH. The brain computed tomography scan also showed fractures in the skull on both temporal areas. The patient was treated conservatively. He was discharge with Glasgow Coma Scale score of 5. CONCLUSIONS: Bilateral temporal EDH in a bilateral temporal AC has never been reported in the literature. The presence of an AC may predispose a patient to complications because of the anatomic changes in the area. It is important to educate asymptomatic patients and their families about these cysts and the importance of avoiding head injury and not being involved in contact sports or military service.