An Intramedullary Tuberculous Abscess of the Conus in a 5-Year-Old Child Presenting with Urinary Dysfunction

OBJECTIVE: To report a case of the primary presence of an intramedullary tuberculous abscess in the conus medullaris with neither a history of contact nor tuberculous infection elsewhere in the body. CASE DESCRIPTION: A 5-year-old boy progressed from urinary hesitancy and frequency to complete urinary retention over the course of 1 month. He was seronegative for human immunodeficiency virus. Magnetic resonance imaging (MRI) showed a D11-L1, well-circumscribed, intramedullary mass within the conus, which was hypointense on T1-weighted imaging and hyperintense on T2-weighted imaging with a thin-walled enhancing capsule. A D11-L2 laminectomy revealed a tense dura and expanded cord with no arachnoidal adhesions. A midline myelotomy and capsular fenestration released thick yellowish, creamy pus. The histology showed loose aggregates of epithelioid cells and a mixed leukocyte population including polymorphonuclear leukocytes and mononuclear cells without formed granulomas. Ziehl-Neelsen staining showed acid-fast bacilli of Mycobacterium tuberculosis. The patient showed rapid improvement of sphincteric function with four-drug antituberculous therapy (ATT). CONCLUSIONS: To the best of the authors' knowledge, an intramedullary conus tuberculous abscess in a young child presenting with urinary dysfunction has never been reported. Perhaps hematogenous spread of M. tuberculosis within the conus, encapsulated proliferation and caseating necrosis (owing to delayed-type hypersensitivity), and an osmotic increase in the fluid content were responsible for its genesis and for the lack of arachnoidal adhesions around the cord. Surgical decompression of the abscess established the diagnosis, increased penetrability of ATT, and decreased the biologic load of bacteria, achieving a good recovery.