Absence of the anterior fontanelle due to a fontanellar bone.

Improved accessibility to supraregional centers in the United Kingdom has led to an increased referral of minor craniofacial anomalies. We have recognized a group of patients referred with absence of the anterior fontanelle and possible associated craniosynostosis. The aim of this study was to assess the group of patients in which the anterior fontanelle was entirely replaced by a single bone, examining associations, relationship to craniosynostosis, and prognostic implications.Eleven patients had fontanellar bones replacing the anterior fontanelle on computed tomographic imaging in the 3-year study period. Five were referred solely because of absence of the anterior fontanelle; and the remainder, because of concern of concomitant craniosynostosis. Five children had associated craniosynostosis (sagittal synostosis, 3; metopic synostosis, 1; and bicoronal synostosis, 1), 1 had acrocallosal syndrome, and 5 had no other craniofacial abnormalities. The patient group with craniosynostosis have been managed in line with the unit protocol and have good early postoperative results (mean postoperative follow-up, 9.4 mo). The 5 patients who had an anterior fontanellar bone as an isolated finding were observed and have developed normally with a mean follow-up of 2 years 1.4 months (range, 8 mo to 3 y 4 mo).Replacement of the anterior fontanelle with a fontanellar bone is an uncommon finding, often associated with craniosynostosis. Cases with craniosynostosis can be treated in line with unit protocols. Isolated anterior fontanellar bones can be managed conservatively without adverse impact on the child.