Arachnoid Cyst with Intracystic Hemorrhage in a Child: Need For Vigilance and Prompt Treatment (P6.324)

Intracranial arachnoid cysts (AC) constitute one percent of all intracranial lesions, most frequently identified in children and mostly located in the middle cranial fossa. They are typically asymptomatic benign non communicating collections of cerebrospinal fluid that occur in relation to the subarachnoid space. Up to 27 per cent cases may be complicated by subacute or chronic subdural hematoma (SDH) or intracranial hemorrhage with minor head trauma, reportedly up to 16 weeks post trauma. Neurological symptoms can be acute and non-localizing. Most common are severe headache and vomiting, or seizures; and can be more subtle such as cognitive, emotional and memory decline from compression of adjacent tissue causing temporal lobe hypoplasia. Treatment is evacuation of SDH, and cystectomy with communication between cyst and cerebral cistern has also been proposed. We report a case of a 7 year old boy admitted with acute bilateral arm paresthesia, in the setting of possible prior head and neck trauma during trampoline play. He frequented the Emergency Department twice in the preceding month with new onset headaches, emesis and neck pain. Physical examination was pain limited, and non-focal. CT C spine did not show signs of trauma. The following day, the patient developed diplopia and was sent for MRI brain which showed large anterior and middle cranial fossa AC with bleed causing significant mass effect and herniation. He was taken for urgent SDH evacuation with drain placement. Post-operatively he rapidly improved back to full baseline functionality. This case highlights the diagnostic difficulties of AC with intracystic hemorrhage, particularly in children with unusual and delayed presentation. It also indicates need for close follow up among patients with AC and minor head trauma. Disclosure: Dr. Naqvi has nothing to disclose. Dr. Katramados has nothing to disclose. Dr. Agarwal has nothing to disclose.