Case of the Week
Section Editors: Matylda Machnowska1 and Anvita Pauranik2
1University of Toronto, Toronto, Ontario, Canada
2BC Children's Hospital, University of British Columbia, Vancouver, British Columbia, Canada
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June 24, 2021
Intradural Extramedullary Tuberculoma of the Spinal Cord
- Background:
- TB of the spinal column typically affects the vertebral bodies and intervertebral discs, as in the case of tuberculous spondylitis, previously known as Pott disease.
- Intradural spinal tuberculoma consists of less than 5% of CNS tuberculoma and intradural extramedullary tuberculoma of the spinal cord (IETSC) without radiologic evidence of vertebral involvement is extremely rare. There are only 35 cases reported in literature.
- According to a review by Dastur et al, 64% of spinal tuberculomas are extradural, 8% intramedullary, 5% intradural extramedullary, and 20% arachnoidal.
- IETSC is thought to represent a sequela of tuberculous meningitis, which can occur anytime but is mostly reported during chemotherapy, between 3 weeks and 1 year. The theorized mechanism of this paradoxical response is hypersensitivity of the host immune system towards protein derivatives of mycobacteria following organism control, leading to arachnoid membrane inflammation, ultimately forming tuberculoma.
- Clinical Presentation:
- Progressive paraplegia with bowel and bladder involvement
- Symptoms of obstructive hydrocephalus (eg, headache, loss of consciousness)
- Key Diagnostic Features:
- Leptomeningeal nodularity and thickening, which are low on T2-weighted sequences and progress to intradural extramedullary mass lesions with cord compression; intramedullary nodules may be seen.
- Diffuse intramedullary high T2 signal due to cord edema progressing to ischemia/syringomyelia, a similar mechanism to inflammatory arachnoiditis
- Diffuse pial and cauda equina enhancement
- MRI of brain may show similar leptomeningeal process intracranially.
- Differential Diagnoses:
- Diagnosis can be made with lumbar puncture and correlation with history. Biopsy may be required if no other systems are involved.
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Granulomatous diseases: Sarcoidosis – correlates with ESR and characteristic chest findings of bilateral hilar lymphadenopathy; other atypical infection (eg, Schistosoma, noninfectious foreign body granuloma – a history of travel to endemic areas or recent surgery)
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Meningioma: T1 iso-/hypointense and slightly T2 hyperintense to spinal cord, avid enhancement with common dural tail, calcification on CT possible, an insidious history, usually solitary but can be present as multiple lesions in the case of NF-2
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Schwannoma: Well-circumscribed, T1-hypointense/T2-hyperintense mass; intense enhancement but may be heterogeneous (cystic change) in larger lesions; if melanocytic, it may be T1 hyperintense.
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Intradural extramedullary spinal inflammatory myofibroblastic tumor: Isointense on T1-weighted sequences and hypointense on T2-weighted sequences; contrast enhancement is intense and homogeneous.
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Carcinomatous meningitis: A history of malignancy or a search for a primary malignancy (eg, CT chest, abdomen, and pelvis); in this case, this was performed and revealed multiple other sites of TB infection.
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Lumbar arachnoiditis: A history of recent lumbar intervention
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Meningeal-based masses in Rosai-Dorfmann disease: Young, male patients with massive cervical lymphadenopathy; histologically, it is characterized by an attenuated infiltration of lymphoplasmacytic cells and histiocytes of varying sizes.
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Treatment:
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First-line anti-TB drugs isoniazid, rifampin (RIF), ethambutol (EMB), and pyrazinamide (PZA)
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In multidrug-resistant TB, the addition of second-line drugs including levofloxacin, moxifloxacin, and linezolid may be necessary.
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In cases of spinal or cauda equina compression, posterior decompression with surgical resection of the intraspinal masses is performed.
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A combination of medical and surgical therapy is required in most cases.
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