Encephalocoele

Case contributed by A.Prof Frank Gaillard

Presentation

Long standing intermittent clear fluid from nose and seizures.

Patient Data

Age: 45 years
Modality: CT

A defect of the right paramedian skull base just to the lateral margin of the olfactory groove  is present. Much of the right frontal sinus is opacified as are the anterior ethmoid air cells and the medial margin of the middle ethmoid air cells on the right. These findings are likely to represent a combination of the opacification and sinus mucosal thickening associated with the meningoencephalocoele.

Differentiation of the two potential pathologies is not possible. Moderate mucosal thickening is present in the maxillary sinuses and in the left anterior and middle medial ethmoidal air cells. The right ostiomeatal unit is opacified secondary to mucosal thickening and the left is barely patent. Previous turbinate surgery noted.

Modality: MRI

Right fronto-ethmoidal encephalocele with prolapse of the anterior right gyrus rectus through the floor of the right frontal sinus, through the anterior ethmoid air cells with bulging of the dural covering into the nasal cavity. The meningoencephalocele appears to contain the right orbitofrontal artery. Associated gliosis in the adjacent frontal lobe noted.

Mucosal thickening within the right frontal sinus, with underlying osteoma, and the ethmoid air cells and maxillary sinuses bilaterally. The hyperdense fluid in the frontal sinus on CT is hypointense to the mucosal thickening on T2 and relatively hyperintense on T1. FLAIR hyperintense deep and periventricular white matter lesions are of a number greater than expected for the patient's age. 

Foci of blooming artefact on SWI in the medial right temporal lobe and the right frontal lobe adjacent to the anterior horn of the lateral ventricle in keeping with previous microhaemorrhage. Previous mini right parietal craniotomy with underlying gliotic tract extending to the right lateral ventricle. Previous resection of the posterior portions of the middle and inferior turbinates.

The patient went on to have a resection and base of skull repair.

Histology confirmed presence of gliotic brain tissue within the meningoencephalocoele.

Some months later the patient represented with right sided symptoms. 

Modality: MRI

The left centrum semiovale lesion shows a rim of fluid signal with central low T2 and high FLAIR signal punctate focus without enhancement. Peripheral diffusion signal and elongated appearance in the periventricular location are highly suspicious for demyelination. 

 When compared to the prior study, the ventricular size has remained similar to previous. Prior right frontal instrumentation tract. Defect to the floor of the third ventricle keeping with prior endoscopic further ventriculostomy. CSF flow is demonstrated through the ventriculostomy. The previously demonstrated right frontal meningoencephalocoele appears similar to previous. New focus of FLAIR hyperintensity in the left centrum semiovale surrounding a central ring of low FLAIR signal, without diffusion signal however no definite restriction is seen. No abnormal susceptibility artefact.

Case Discussion

This individual has three distinct, albeit to some degree related conditions: 1) meningoencephalocoele which resulted in gliosis of the frontal lobe which in turn resulted in 2) seizures. 3) demyelination, presumably multiple sclerosis given the presence of quiescent lesions on the first scan, seems harder to reconcile with the former, however incidence of MS is known to be higher in patients with head injury, so probably there is increased risk also in individuals with other cranial insults. 

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Case Information

rID: 45354
Case created: 23rd May 2016
Last edited: 3rd Jun 2016
Inclusion in quiz mode: Included

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