Prominent basal emissary foramina in syndromic craniosynostosis: correlation with phenotypic and molecular diagnoses

Abstract

Background and purpose: Jugular foraminal stenosis (JFS) or atresia (JFA) with collateral emissary veins (EV) has been documented in syndromic craniosynostosis. Disruption of EV during surgery can produce massive hemorrhage. Our purpose was to describe the prevalence of prominent basal emissary foramina (EF), which transmit enlarged EV, in syndromic craniosynostosis. Our findings were correlated with phenotypic and molecular diagnoses.

Methods: We reviewed the medical records and imaging examinations of 33 patients with syndromic craniosynostosis and known fibroblast growth factor receptor (FGFR) mutations. All patients underwent CT and 14 MR imaging. The cranial base was assessed for size of occipitomastoid EF and jugular foramina (JF). Vascular imaging studies were available from 12 patients. A control group (n = 76) was used to establish normal size criteria for JF and EF.

Results: Phenotypic classification included Crouzon syndrome (n = 10), crouzonoid features with acanthosis nigricans (n = 3), Apert syndrome (n = 10), Pfeiffer syndrome (n = 4), and clinically unclassifiable bilateral coronal synostosis (n = 6). EF > or = 3 mm in diameter and JFS or JFA were identified in 23 patients with various molecular diagnoses. Vascular imaging in patients with JFS or JFA and enlarged EF revealed atresia or stenosis of the jugular veins and enlarged basal EV. JFA was seen in all patients with the FGFR3 mutation with crouzonoid features and acanthosis nigricans. Four patients had prominent EF without JFS. Six patients had normal JF and lacked enlarged EF.

Conclusion: Enlarged basal EF are common in syndromic craniosynostosis and are usually associated with JFS or JFA. Bilateral basilar venous atresia is most common in patients with the FGFR3 ala391glu mutation and crouzonoid features with acanthosis nigricans, but may be found in patients with FGFR2 mutations. Skull base vascular imaging should be obtained in patients with syndromic craniosynostosis with enlarged EF.

fig 1.

Case 1: Eight-year-old girl with crouzonoid features, acanthosis nigricans, and FGFR3 ala391glu mutation. A, Helical CT shows bilateral JFA (arrows) and a large left mastoid emissary foramen (arrowheads). B, Axial collapsed maximum intensity projection (MIP) from 3D TOF MRV (53/6.9/1 [TR/TE/excitations]) reveals atresia of the right transverse and sigmoid sinuses and the both internal JV (arrowheads). Large occipitomastoid EV arise from the left transverse and sigmoid sinuses (arrows).

fig 2.

Case 3: Three-year-old boy with crouzonoid features, acanthosis nigricans, and FGFR3 ala391glu mutation. A, Axial CT shows a large central occipital emissary foramen (arrow). A small left mastoid emissary foramen is seen (arrowhead). B, Axial CT 2 years after surgical clipping of the occipital emissary vein (arrowhead) shows marked enlargement of the left mastoid emissary foramen (arrow). C, Digital subtraction cerebral angiogram, frontal projection, shows atresia of the right sigmoid sinus and lateral portion of the left sigmoid sinus (arrows) and atresia of both internal JV. There are large left mastoid EV arising from the proximal left sigmoid sinus (arrowheads).

fig 3.

Case 5: Three-year-old girl with Pfeiffer syndrome and FGFR2 cys342arg mutation. Frontal MIP of a CT venogram shows occlusion of the transverse sinuses (arrowheads) and large duplicated occipital sinuses (arrows). fig 4. Case 20: Ten-year-old girl with Pfeiffer syndrome and FGFR2 ser354cys mutation. Helical CT shows a large right occipitomastoid emissary foramen (arrowhead). The right jugular foramen is stenotic, with prominent septations (arrow). The left JF appeared stenotic on a caudal image of the skull base (not shown)

fig 5.

Case 12: A 21-month-old girl with Crouzon syndrome and FGFR2 cys342tyr mutation. Axial collapsed MIP from 3D TOF MRV (53/6.9/1) 20 months after the initial CT shows JFS. There is stenosis of both transverse and sigmoid sinuses and the internal JV (arrowheads). There are large, right, occipitomastoid EV (arrows). fig 6. Case 23: Three-year-old boy with clinically unclassified, bilateral, coronal synostosis and FGFR2 ala314ser mutation. Axial T1-weighted MR imaging (450/14/1) reveals flow voids within large bilateral mastoid EV (arrows). The JV are stenotic (arrowheads)

fig 7.

Case 24: Two-year-old girl with Crouzon syndrome and FGFR ser354cys mutation. A, Axial CT shows that the JF are not stenotic (asterisks). B, Magnified, oblique, frontal MIP from 3D TOF MRV (53/6.9/1) reveals a focal stenosis at the junction of the right sigmoid sinus with the internal JV (arrow). There is a large right mastoid EV (arrowheads).