Atypical extensive extratemporal hyperpneumatization of the skull base including the cervical spine: case report and review of the literature.

STUDY DESIGN

Case report and clinical discussion.

OBJECTIVE

To describe a rare case of hyperpneumatization of the skull base including the cervical spine with the atlas bone.

SUMMARY OF BACKGROUND DATA

Initial imaging studies of physically traumatized patients consist of conventional radiographs. An atypical radiolucency is often misdiagnosed as a primary malignancy or a secondary osteolytic metastasis. Further imaging studies may reveal an underlying atypical hyperpneumatization as a very rare benign differential diagnosis. Pathophysiologically, embryological developmental anomalies as well as an elevated pressure to the middle and inner ear are discussed.

METHODS

We present a symptomatic 40-year-old man with conventional radiographs, after computed tomography and magnetic resonance imaging examinations.

RESULTS

Imaging studies reveal an uncommon radiolucency of the skull base including the atlas bone, free air beneath the mastoid bone, stylomastoid foramen, epidural air adjacent to the atlas bone, and surrounding soft-tissue emphysema.

CONCLUSION

Atypical radiolucency may represent a very rare benign hyperpneumatization of the skull base, which may include the craniocervical junction. Because of microfractures of the thinned and consecutive, less stable bones, this also can lead to free air and soft-tissue emphysema, which has not been described previously. Special care should be taken to identify epidural free air because of a possible communication of the epidural space with the external environment. Harmful activities and especially high-speed trauma could result in fractures of the cervical spine due to decreased stability of the hyperpneumatized bones.