Laron Syndrome Abnormalities: Spinal Stenosis, Os Odontoideum, Degenerative Changes of the Atlanto-odontoid Joint, and Small Oropharynx

Patient 11. Sagittal T1-weighted MR image (450/25/2, 3.2-mm thickness) of the cervical spine shows that the spinal canal is of normal width. Dens is intact. Arrows indicate the level of measurement of soft-palate thickness.

Patient 3.

A and B, Lateral flexion (A) and extension (B) radiographs of the cervical spine. Dens is not visualized. Atlantoaxial instability is demonstrated. Note the small vertebral bodies and the narrow cervical canal.

C, Sagittal reconstruction of CT data obtained at C1-C2 shows a gap between the base of the dens and the small bone above it, compatible with os odontoideum.

D, Sagittal T2-weighted MR image (4600/160/1) shows stenosis of the cervial spine. A focus of myelomalacia is seen at the C1-C2 level. High signal intensity from the region of the disrupted dens probably represents reactive tissue.

Patient 9.

A, Lateral radiograph of the cervical spine shows the dens, which appears thickened and sclerotic.

B, Sagittal reconstruction of CT data obtained at C1-C2 shows no malformation of the dens. Note the cortical thickening and the narrowing of the atlantoaxial joint, possibly compatible with degenerative changes.

C and D, Sagittal T1-weighted (C; 500/20/2, 4-mm thickness) and T2-weighted (D; 4000/160/1, 4-mm thickness) MR images show a thin dens. Note the mild compression of the subarachnoid space at the C1-C2 level owing to cortical thickening and sclerosis of the dens.