RESUMO
INTRODUCTION: Colloid cysts are intracranial lesions with an estimated incidence of three individuals per million people per year. They are benign tumours in the anterosuperior portion of the third ventricle. The normal flow of cerebrospinal fluid may be interrupted by a large cyst that obstructs the foramen of Monro. The associated signs and symptoms cover a wide range of features, from non specific headaches to intracranial hypertension data; some colloid cysts occur at the acute onset of hydrocephalus and can lead to a sudden death. CASE REPORT: We present the case of a patient with a colloid cyst in the anterior roof of the third ventricle, with the presence of a dysfunctional ventriculo peritoneal bypass valve, which had been introduced three years earlier. Both events contributed to the development of a hydrocephalus with clinical manifestations of intracranial hypertension. The images obtained by magnetic resonance (MR) revealed the presence of a hyperintense mass of variable density in the roof of the third ventricle and in its rostral face; the image was hyperintense in T1 and isointense in T2. The patient was submitted to an endoscopic cisternoventriculostomy to allow the surgical drainage of the colloid cyst, and management was continued in the outpatients department of the Neurosurgery Service. CONCLUSIONS: In this paper we discuss the main characteristics of the colloid cyst, some considerations on its presentation in MRI are presented and a brief survey of the literature is also conducted.