Introduction: The fossa navicularis is an anatomical skull base variant. It represents a bony notch in the skull base, thought to be very rare and benign until recently, when 3 separate cases of intracranial infection associated with this finding have been reported.
Methods: We reviewed the scientific searches – PubMed Central, EMBASE, Google Scholar, Scopus database, Cochrane database and Science Research, using the key words: fossa navicularis; canalis basilaris medianus; and pharyngeal fossa. We identified the papers where these terms were used, and described the unique features and clinical importance of this distinctive skull base radiological finding.
Results: Our literature search covered papers from the 19th century till modern day literature. The earlier authors described ‘fossa navicularis’ as a very rare skull base finding. However more recently, 3 cases have been reported with associated clival or intracranial infection. To the best of our knowledge, this will be the 4th case reported in the literature and the only one that has been surgically repaired via an endonasal endoscopic approach. We present a 9 year old female who had presented with prior recurrent episodes of meningitis and was diagnosed with fossa navicularis. This skull base morphological anomaly should be considered in the differential diagnoses for unexplained skull base infective pathology.
Conclusions: Fossa navicularis is a notch-like defect seen in the clivus. It is an anatomic skull base variant previously described in the literature as very rare. The cases reported were all associated with intracranial infection. This skull base morphological anomaly should be considered in the differential diagnoses for unexplained skull base infective pathology.
Patient Care: As high resolution CT and MRI becomes increasingly accessible, we propose that careful scrutiny of the skull base will be beneficial for determining the real incidence of this anatomic variant and will also aid prompt diagnosis of the aetiologic factor in relevant infective scenarios. Our review suggests that the incidence might be higher than previously reported.
Learning Objectives: This will help to highlight the importance of diagnosing this skull base anatomical variant especially in the pediatric population, and prevent the possible clinical consequences.
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