CASE 11715 Published on 06.04.2014

Sphenoid lateral spontaneous cephalocele

Section

Neuroradiology

Case Type

Clinical Cases

Authors

Carolina Diaz Angulo, Olalla Vasquez Muiños, Enrique Flores Rios, Jóse Luis Diaz Vilariño, Marta Maria Seoane Dopico, Sonia Patricia Mosteiro Añon, Alejandro Diaz García

Complejo Hospitalario Universitario A Coruña (CHUAC);
Avenida Xubias 84.
15006 A Coruña, Spain.
Email: mir.radiologia@gmail.com
Patient

80 years, female

Categories
Area of Interest Neuroradiology brain ; Imaging Technique CT, MR
Clinical History
An 80-year-old female patient, with clinical history of hypertension and diabetes, was brought to our hospital after suffering a facial injury from a fall while cleaning her bathtub. No episode of unconsciousness or any other neurological symptom was referred. Physical examination demonstrated Glasgow 15/15, orbital oedema and a left frontal haematoma.
Imaging Findings
Non-enhanced computed tomography (CT) demonstrated no traumatic craniofacial complications beyond a periorbital hematoma. Incidentally a skull defect was found in the greater wing of the left sphenoid bone, with a posterior cortical rupture and intracranial protrusion through the defect. [Fig. 1 a, b]

Magnetic Resonance (MR) was made to confirm CT findings. MR showed a skull expansive defect in the left greater wing of the sphenoid bone, with a posterior cortical discontinuity through which cerebrospinal fluid, hyperintense in T2-weigthed images and hypointense in FLAIR and T1-w images, and the anterior pole of the temporal lobe, isointense to cerebral parenchyma in all sequence, herniates. [Fig. 2 a, b, c]
Discussion
Cephalocele is the term for a herniation of neural tissue through a skull defect. It is called meningoenceohalocele o encephalocele when cerebrospinal fluid (CSF), meninges and brain parenchyma protrude through the skull defect; and meningocele when only CSF and meninges are herniated. [1, 2]

Cephalocele can be either spontaneous, a congenital development defect or secondary to previous trauma, surgery, tumours, sphenoid dysplasia or osteoradionecrosis. [1] In our case the cephalocele is an incidental finding of spontaneous origin in a patient with non-relevant clinical history. Actual trauma cannot be the origin since it needs time for its formation.

It is usually a midline skull defect more frequently found in the occipital bone. However, spontaneous cephaloceles occur off line, characteristically in the lateral sphenoid bone, as in our case. These lesions are known as sphenoid lateral spontaneous cephalocele (SLSC), they are more frequently found in middle-aged obese women, are smaller than usual cephalocele and are not associated to brain malformations. [1]

Two subtypes of SLSCs have been described. Type 1 herniates into a pneumatized lateral recess of the sphenoid sinus and can be associated to CSF leak. [2, 3] Type 2 SLSC herniates into the greater wing of the sphenoid and may present with seizures and/or headaches, and can also be found incidentally, is less frequent than type 1 SLSC. [1, 4] Arachnoid pit has been postulated as a possible cause of SLSC. [4]

CT is the best modality to demonstrate bone and vascular anatomy around the defect. MR is more useful to distinguish herniated cranial tissue, especially T2-wighted images that allow a better differentiation of brain parenchyma, cerebrospinal fluid and vascular components. In T1 weighted images neural protruded tissue is hypointense, in T2-w images CSF is hyperintense and brain parenchyma isointense or hyperintense, depending on secondary gliosis. Contrast-enhanced T1-w images show no enhancement. [1]

CT and MR are complementary imaging techniques and it is recommended to use both for presurgical evaluation. CT angiography is needed to demonstrate relationship of dural sinuses to bony defect. Untreated lesions can be associated to headache and seizures, and increase the risk for meningitis, SLSC type 2 can be treated medically o surgically if symptoms are present, but it can also be an incidental finding with no treatment needed as in our case. [1]
Differential Diagnosis List
Sphenoid lateral spontaneous cephalocele type 2
Sphenoid defect in neurofibromatosis type 1
Sphenoid lateral spontaneous cephalocele type 1
Final Diagnosis
Sphenoid lateral spontaneous cephalocele type 2
Case information
URL: https://www.eurorad.org/case/11715
DOI: 10.1594/EURORAD/CASE.11715
ISSN: 1563-4086

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