A Rare Diagnosis of Aseptic Hypertrophic Pachymeningitis: A Case of Mycobacterial Tuberculosis Origin

Tubercular meningitis is a rare yet devastating type of extrapulmonary tuberculosis (TB) posing great diagnostic challenges due to the nonspecific clinical presentation of the patients. Here, we present a rare diagnosis of hypertrophic pachymeningitis due to Mycobacterium tuberculosis. A 36-year-old male presented with a history of headaches and giddiness for one month. Neurological examination revealed hypo-reflexive triceps and ankle reflexes. Routine blood tests and autoimmune workup were normal. Brain MRI with contrast revealed diffuse dural thickening, focal leptomeningeal enhancement in the right temporal sulci, and enhancement in both the frontal and parietal convexity and the falx cerebri and along the tentorium cerebelli. Cerebrospinal fluid (CSF) analysis revealed elevated proteins, suggestive of aseptic meningitis. Meningeal biopsy revealed a chronic ill-formed granulomatous inflammatory lesion with occasional acid-fast bacilli, consistent with tubercular pachymeningitis. The patient was administered intravenous (IV) methylprednisolone for five days, following which the symptoms subsided. He was advised tablet prednisolone on discharge, and immunomodulation with rituximab was recommended as outpatient treatment. Hypertrophic pachymeningitis is a rare diagnosis characterized by the inflammation and fibrosis of the dura matter due to a diverse etiology. Tubercular etiology must be considered when the routine laboratory tests are negative, and the diagnosis should be confirmed by meningeal biopsy. The treatment of the underlying cause and corticosteroids remain the mainstay management of hypertrophic pachymeningitis. Hence, mycobacterial tuberculosis should be considered as a possible differential diagnosis while evaluating hypertrophic pachymeningitis, especially when the routine laboratory tests and immunological workup are negative.