Section Editor: Sandy Cheng-Yu Chen, M.D.
Taipei Medical University Hospital, Taipei, Taiwan
Figure Caption
Biparietal osteodystrophy is a rare condition of unknown etiology in which there is thinning of the parietal bones. Its prevalence is about 0.4% of normal skulls, but it is more common in elderly women with osteoporosis. Imaging findings include oval-shaped lucencies in the upper portions of parietal bones on lateral radiographs (arrows in A). CT reveals bilaterally symmetrical loss of the diploic space with resorption of the outer table (white arrows in B and C) and the inner table (yellow arrows in B and C) being intact.