Clival osteomyelitis resulting from spread of infection through the fossa navicularis magna in a child

Abstract

The fossa navicularis is a notch-like bone defect in the basiocciput that has been hitherto considered as an anatomical variant of the clivus and not previously described as a potential source of clival or skull base pathology. We report the imaging findings in a 5-year-old child who presented acutely with a retropharyngeal abscess and osteomyelitis of the clivus. Imaging after treatment revealed a "notch-like" defect in the anterior clivus consistent with a fossa navicularis. Based on these appearances, we postulate that the lymphoid tissue of the pharyngeal tonsil residing in the fossa navicularis served as a route through which infection spread and subsequently developed into clival osteomyelitis, which is a rare diagnosis. This case is unique, and we believe that the presence of this variant in young children may be important and is not merely an anatomical curiosity.

Prevalence of fossa navicularis among cleft palate patients detected by cone beam computed tomography

“…Although fossa navicularis does not require an intervention, it may lead to the spread of an infection to the base of the skull. [9][10][11] Therefore, anatomy of this defect, which can be indicated by typically well-corticated margins, should be identified and reported by the dentomaxillofacial radiologists.…”

Multi–Detector-Row Computed Tomography Imaging of Variant Skull Base Foramina

“…15 Rarely, the lymphoid tissue of the pharyngeal tonsil residing in the fossa navicularis served as a route through which infection spread and led to clival osteomyelitis. 16 In addition, canalis basilaris medianus can be associated with enterogenous cysts. 17…”

Skull base osteomyelitis and potential cerebrovascular complications in children

“…There is high signal on diffusion-weighted imaging B=1000 (e, arrow) and reduced apparent diffusion coefficients values (f, arrow) central skul base osteomyelitis, brain MRI may reveal intracranial spread of the infection with dural involvement beyond the cavernous sinuses and formation of petroclival abscess and small epidural empyemas at the craniovertebral junction (Fig. 6) [20,21]. Soft-tissue involvement of the cavernous sinus may be present even without signs of sinus thrombosis.…”