Spinal Hypertrophic Pachymeningitis in Antineutrophilic Cytoplasmic Antibody-Negative Vasculitis: A Case Report.

Hypertrophic pachymeningitis (HPM) is a rare but extremely debilitating disease. It is even rarer for HPM to be seen in association with antineutrophil cytoplasmic antibody (ANCA)-negative vasculitis. In this case, we are presenting HPM that was diagnosed in a 28-year-old female patient who presented with worsening back pain. Imaging revealed dural-based enhancing masses affecting the thoracic spinal cord with compression. Infectious etiologies were ruled out and a total of three biopsies failed to show any evidence of granulomatous inflammation, malignancy, or evidence of immunoglobulin G4-related disease. ANCA was negative on repeated testing. The patient was managed with repeated short courses of steroids that resulted in symptomatic control as well as radiological stability of the disease. This is an extremely rare case of atypical presentation of spinal HPM that is likely associated with granulomatous and polyangiitis without other manifestations of the disease except for nasal septal perforation. This case is a supplement to a limited body of knowledge and established cases of HPM in ANCA-negative, ANCA-associated vasculitis.