Primary Temporal Bone Meningioma Presenting as Chronic Mastoiditis and Sigmoid Sinus Thrombosis: Report of a Case with Literature Analysis

Primary extra cranial meningioma of the ear and temporal bone are exceedingly rare, making up less than 1% of all meningiomas. Histologically, they are indistinguishable from their intracranial counterpart. The histopathologic diagnosis is often challenging, and the differential diagnosis for neoplasms in this unusual location is quite extensive. We report a 64-year-old male patient with history of seizures who presented with coalescing mastoiditis and sigmoid sinus thrombosis. CT and MRI findings were suggestive of a chronic inflammatory process. Operative findings included a flesh-colored mass extending from the mastoid antrum posteriorly towards the Sigmoid sinus. Intraoperative consultation was requested, yielding a diagnosis favoring squamous cell carcinoma, and the decision was made to end the procedure. Additional tissue was submitted for permanent evaluation, and biopsy demonstrated a grade 1 meningioma, supported by morphologic features and immunophenotype. The clinical and histologic findings of the patient are discussed, and we emphasize the challenging nature of this rare entity, particularly with regards to intraoperative analysis. In addition, English literature is reviewed.