Chiari type III malformation: Case report and review of literature.

Chiari III (CM III) is the rarest of the Chiari malformations, characterized by high cervical or occipital encephalocele and osseous defects, associated with herniation of the posterior cerebral fossa contents through the foramen magnum. We report the case of a female newborn, with a cervico-occipital mass, hypotonia and sharp osteotendinous reflexes in the lower limbs. An MRI was performed showing a low occipital encephalocele with caudal displacement of cerebellar tonsils. Because of its high contrast resolution, MRI is more useful than CT, preoperatively, to assess the content of the encephalocele. MRI can identify the position of the brain stem and spinal cord, so that they are preserved during the surgical procedure.