Glimpse into Pathophysioloqy of Sellar Arachnoid Cysts

BACKGROUND: Sellar arachnoid cysts are a rare occurrence but may impinge on vital parasellar anatomy and thus are often symptomatic. The etiology of sellar arachnoid cysts is contentious, fueled by heterogeneity in cyst wall structure and contents between cases. The ball-valve mechanism is 1 of 2 predominant theories describing their formation, which contends that an aperture in the diaphragm allows cerebrospinal fluid to enter the cyst, propelled by pulsatile flow, but its egress is obscured by the pituitary during the ebb of the pressure wave. CASE DESCRIPTION: Here we present a case of a 51-year-old female with a symptomatic sellar arachnoid cyst. She underwent an endoscopic transphenoidal fenestration which alleviated her symptoms. CONCLUSIONS: Intraoperative video evidence during arachnoid cyst fenestration supports the ball-valve theory of sellar arachnoid cyst development.