Temporal lobe encephalocele in the lateral recess of the sphenoid sinus presenting with intraventricular tension pneumocephalus

Abstract

A basal encephalocele often shows an insidious clinical course. Only two cases of temporal lobe encephalocele accompanied with tension pneumocephalus have previously been reported. In this paper, we describe a case of lateral sphenoid sinus encephalocele presenting with intraventricular tension pneumocephalus. A 54-year-old man was referred to our institution presenting with intraventricular tension pneumocephalus. He had undergone ventriculoperitoneal shunt placement for postmeningitis hydrocephalus 3 months before this admission. Precise imaging examinations detected evidence suggestive of a lateral sphenoidal sinus recess encephalocele. Endoscopic transnasal approach was performed for surgical repair of the encephalocele. The encephalocele was removed with subsequent repair of the bony defect. Histological examination showed that the encephalocele includes a part of the ventricular system. This indicates that air might enter directly into the ventricular system after rupture of the temporal lobe encephalocele. A lateral sphenoid sinus encephalocele would potentially cause intraventricular tension pneumocephalus, although pneumocephalus is an extremely unusual complication of this type of basal encephaloceles.

Keywords: Encephalocele; endoscopic surgery; pneumocephalus; sphenoid sinus.

Figure 1

A plain CT image showing a marked pneumocephalus exclusively in the lateral ventricle.

Figure 2

(A) Preoperative coronal CT and (B) T2-weighted MRI demonstrating a temporal lobe encephalocele protruding in the left lateral recess of the sphenoid sinus.

Figure 3

(A) Intraoperative view with a 30-degree angled endoscope showing a pulsating membranous tissue bulge (arrow) in the lateral recess of the sphenoid sinus. (B) Endoscopic view illustrating a bony defect repaired with a bone fragment (arrow).

Figure 4

Photomicrographs of histological sections of the surgical specimen. (A) Hematoxylin and eosin staining showing a layer of degenerative ependymal cells in line (original magnification, 200 × ). (B) A layer of ependymal cells exhibiting dotted immunoreactivity for epithelial membrane antigen (arrows; epithelial membrane antigen immunohistochemistry, original magnification, 200 × ). (C) A focal staining for neurofilamentous proteins (neurofilamentous proteins immunohistochemistry, original magnification, 100 × ).