Dolichoodontoid. A rare cranio-cervical anomaly--MRI findings.

The case of a 40-year-old woman with a dolichoodontoid, a rare congenital anomaly of the cranio-cervical region, is presented. Due to summation image and overlying bony structures, plain radiographs in two planes were inconclusive. MRI revealed the hyperplasia of the odontoid process, allowed a grading of the subtype of this disorder and demonstrated its relationship to the neural structures within the foramen magnum and the upper cervical spine. Additional inflammatory disease, suspected in this patient with long standing rheumatoid arthritis could be excluded by MRI.