Rhomboencephalosinapsi is an extremely rare malformation of the posterior cranial fossa, characterized by the fusion of the cerebellar hemispheres, the medial peduncles, the dentate nuclei and the hypogenesis of the cerebellar vermis.It is considered a sporadic malformation due to an autosomal dominant mutation that arises "de novo"; The incidence at birth is estimated at around 0.13% [1,2].In this article we present the case of a male patient of 6 years of age with global delay of the diagnosis diagnosed with rhombencephalosinopsis and the MRI findings made in the Central Military Hospital. CaseA 6-year-old male patient with a global developmental delay diagnosed with rhombencephalosinopsis [1,2].Magnetic resonance imaging (MRI) practiced the following findings: