A Case of Cleidocranial Dysplasia Confirmed by 3D CT of the Cranium

Cleidocranial dysplasia (CCD) is an autosomal dominant disorder characterized by absence or hypoplasia of the clavicles, an open fontanelle (1–4), and malaligment of the teeth (2). In previous reports, CCD was diagnosed by plain X-ray films of the cranium and chest. These may show widened fontanelles, wormian bones in the cranium, and a bell-shaped thorax with absence or hypoplasia of the clavicles (1–4). We found 3D CT more clearly showed the open fontanelle than did a radiograph of the skull, and we believe 3D CT is helpful in the diagnosis of CCD in older children.

Our patient was a 4-year-old boy of short stature. Hyperterolism and a broad and flat nasal bridge was noted. On physical examination, a four-finger-width open anterior fontanelle was noted. Chest film showed a bell-shaped thorax with a narrowed upper portion and complete absence of both clavicles. The skull films showed multiple wormian bones in the cranium (Fig 1A); however, the open fontanelle was not seen in the anteroposterior view, but was suspicious on the lateral view (Fig 1B). A spiral CT scan with 4-mm slice thickness and 3D reconstruction of the cranium was performed (Fig 1C).

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fig 1.

A, B, Skull films. In the anteroposterior view (A), wormian bones are noted (arrows); however, the open fontanelle is not clearly visible. In the lateral view (B), defect of the cranium in the fontanelle region is noted (arrowhead).

C, 3D CT of cranium. The open anterior fontanelle is clearly visible.

Although many children with CCD have an open fontanelle (2, 4), this finding is not always clear in older children (1, 4) because, with increasing age, there is more mineralization in the cranium, and the calvarial bone thickness increases. In the anteroposterior view, the opened fontanelle is superimposed by the occipital bone (Fig 1A), so it is difficult to see. With 3D CT, however, the open fontanelle can be clearly delineated (Fig 1C) and will correspond to the presence of a widened fontanelle. We recommend 3D CT of the cranium be performed in patients with CCD.