Spontaneous regression of a symptomatic pineal cyst after endoscopic third-ventriculostomy

With the advent of modern diagnostic tools for neuroimaging the incidental detection of pineal cysts in asymptomatic subjects has increased. Only rare ly do pineal cysts present with the clinical signs and symptoms of increase d intracranial pressure or with neurological deficits in relation to compre ssion and distortion of the adjacent nervous structures and cerebrospinal f luid pathways. While asymptomatic cysts are considered to be normal variant s for which no further investigations are usually required, surgical treatm ent is suggested for symptomatic cysts, with the goal of eliminating the bl ock in the cerebrospinal fluid circulation and/or the mass effect exerted b y the lesion. in this report we describe a pediatric case of symptomatic pi neal cyst, revealed by repeated episodes of headache caused by secondary ob structive hydrocephalus. Following an endoscopic third-ventriculostomy, ser ial magnetic resonance imaging studies demonstrated that not only had the v entriculomegaly resolved but also that the pineal cyst had regressed over t ime. A to-and-fro movement of fluid through the cyst wall, the direction of which depends on the equilibrium existing between the inner pressure of th e cyst and the outer cerebrospinal fluid pressure, is suggested as a possib le mechanism accounting for this unexpected result - to our knowledge, the first reported in Literature.