Spontaneous intraparenchymal otogenic pneumocephalus: A case report and review of literature

Abstract

Background: Pneumocephalus is commonly associated with head and facial trauma, ear infection, or surgical interventions. Spontaneous pneumocephalus caused by a primary defect at the temporal bone level without association with pathological conditions is very rare. Few cases have been published with purely intraparenchymal involvement. We describe a rare case of spontaneous pneumocephalus arising from the mastoid cells with intraparenchymal location and present an extensive review of the existing literature.

Case description: A 57-year-old woman presented a brief episode of sudden otalgia in her left ear that was followed by a motor aphasia. Imaging revealed a left temporal intraparenchymal pneumocephalus in a close relationship with a highly pneumatized temporal bone. Left temporal craniotomy and decompression were performed. Further subtemporal exploration confirmed a dural defect and other osseous defects in the tegmen tympani, which were both consequently closed watertight.

Conclusion: Although extremely rare, a spontaneous intraparenchymal pneumocephalus with mastoidal origin should be considered as a possible diagnosis in patients with suggestive otological symptoms and other non-specific neurological manifestations. Surgery is indicated to repair bone and dural defects.

Keywords: Intraparenchymal; pneumocele; spontaneous pneumocephalus; tegmen tympani; temporal bone.

Figure 1

Pre-operative imaging. (a) CT shows a single hypodense lesion in the left temporal lobe with mild mass effect. (b) Plain skull radiograph demonstrating a bubble air. (c) Axial and coronal CT with bone window shows the close relationship of pneumocephalus with a highly pneumatized temporal bone. (d) Coronal FLAIR MR shows the pneumocele in the left inferior and middle temporal gyrus and post-gadolinium T1-weighted axial MR shows no pathological enhancement

Figure 2

Operative findings. Extradural subtemporal approach to the tegmen tympani area showed a 5-mm bone defect (blue arrow) in close relationship with an adjacent dural defect (red arrow), through which cerebrospinal fluid leak was observed. Other smaller bony defects of about 2 mm (green arrow) were also found, but without any relationship with dural hole

Figure 3

Postoperative imaging. (a) Axial CT and (b) axial post-gadolinium T1-weighted MR show a total resolution of the pneumocephalus