[Chiari type I malformation in a patient with Poland's syndrome].

Chiari malformation type I and Poland's syndrome are two rare diseases and their simultaneous presentation had not been previously described in the literature. We report the case of a 27 year old male with history of Poland's syndrome, who referred headache and motor impairment of the intrinsic muscles of the left hand. In a cervical spine MR a Chiari I malformation with syringomyelia from C1 to T2 was found, which was treated by foramen magnum decompression, dural plasty and removal of the posterior arch of the atlas. A discussion of the embryological mechanisms that might be involved in the coexistence of these two entities is presented, emphasizing the role of para-axial mesoderm.