CASE 3394 Published on 24.06.2005

Metopic craniosynostosis (Trigonocephaly)

Section

Paediatric radiology

Case Type

Clinical Cases

Authors

Rea D, Ryan S

Patient

2 months, male

Clinical History
A two-month-old male baby presented with cranial dysmorphism, which had been present since birth.
Imaging Findings
Clinical context & Imaging: A two-month-old male was noted to have cranial dysmorphism which was present since birth. There was an evidence of hypotelorism and a keel shaped forehead with a palpable ridge. The child was otherwise physically and developmentally normal. Skull radiographs demonstrated hypotelorism. A non-contrast 3D CT of the skull and brain was later performed, which revealed no cerebral intracranial abnormality. Axial bone window images and the three-dimensional reformatted shaded surface display of the skull were created, which also demonstrated pointing or beaking of the midline of the frontal bone. Corrective cranio-facial surgery was performed with an excellent clinical outcome.
Discussion
Craniosynostoses may be grouped into two categories. The term primary craniosynostosis refers to a premature fusion of at least one cranial suture due to a developmental error. Secondary craniosynostosis relates to a premature fusion resulting from other causes such as the effect of teratogens or due to the lack of a normal brain growth. Craniosynostosis may be seen in isolation in normal individuals or as part of a syndrome associated with other developmental anomalies. Approximately 15% of affected children are syndromic, with other associated anomalies such as fusion of the fingers in Apert’s syndrome. Metopic craniosynostosis (Trigonocephaly) arises due to a premature fusion of the metopic suture. This occurs in approximately 67 per 100,000 live births with a male to female ratio of 3.3 to 1. Metopic craniosynostosis accounts for only 4% of all the craniosynostoses after sagittal, coronal, and multiple craniosynostoses. Only a portion of the suture needs to be fused, to cause craniosynostosis. Metopic craniosynostosis results in a triangular keel shape to the forehead. It may be diagnosed by a fetal ultrasound procedure, with the detection of the abnormal shape of the forehead being possible as early as the second trimester. The diagnosis can be made from the clinical appearance of the child. Skull radiographs may show the associated hypotelorism but will not show the abnormal configuration of the frontal bones unless a submento-vertical view is included. 3D CT scanning also shows the orbital hypotelorism as well as the keel shaped frontal bone, retruded lateral orbital rims and a narrowed bitemporal width. Intracranial structures are usually normal but there may be associated midline anomalies, such as holoprosencephaly.
Differential Diagnosis List
Metopic craniosynostosis.
Final Diagnosis
Metopic craniosynostosis.
Case information
URL: https://www.eurorad.org/case/3394
DOI: 10.1594/EURORAD/CASE.3394
ISSN: 1563-4086