Isolated Tuberculoma Mimicking Foramen Magnum Meningioma in the Absence of Primary Tuberculosis: A Case Report

Central nervous system tuberculosis is a devastating complication of systemic tuberculosis. Intradural extramedullary (IDEM) tuberculoma at the foramen magnum is rare, and mimics en plaque meningioma. We report the case of a 53-year-old woman who presented with dysesthesia of the tongue and lower cranial nerve (CN) palsy, with onset 4 months prior to admission. The neurologic examination revealed left upper-limb weakness and hypoesthesia on the sole and dorsum of the left foot. Other physical examinations revealed no features of tubercular infection. Laboratory investigations likewise showed no signs of infection or inflammation. Magnetic resonance imaging of the brain showed an IDEM mass originating from the left intradural surface at the foramen magnum extending to the C2 segment and compressing the brainstem and upper cervical cord. The mass was isointense/hypointense on T1- and T2-weighted images and homogeneously-enhanced on postcontrast images. The lesion also exhibited the dural-tail sign and was preoperatively diagnosed as en plaque meningioma. The patient underwent surgery via the left transcondylar fossa approach with partial laminectomy of the atlas. Intraoperatively, the mass exhibited a dural origin and encased the vertebral artery and lower CNs, with strong adhesions. While the histopathological study of the mass was strongly suggestive of tuberculoma with multifocal granulomas, caseous necrosis, and Langerhans giant cells, extensive diagnostic studies failed to detect Mycobacterium tuberculosis itself. Although the patient had recurrence with multisystem involvement, she responded well to antitubercular treatment. IDEM tuberculoma of the foramen magnum may present as en plaque meningioma. Histopathology is required for a definitive diagnosis. Prompt surgical resection and decompression with adequate antitubercular treatment yield better neurological outcomes.