Paraplegia Caused by IgG4-Related Hypertrophic Pachymeningitis With an Elevated Cerebrospinal Fluid Immunoglobulin G4 Concentration.
Doyama Hisaki H, Matsumoto Yasuko Y, Kurosaka Akiho A, Kobayashi Motoya M et al.
Immunoglobulin G4-related hypertrophic pachymeningitis (IgG4-RP) is a rare manifestation of immunoglobulin G4 (IgG4)-related disease and an uncommon cause of hypertrophic pachymeningitis (HP). Because serum IgG4 concentration is not necessarily elevated, the diagnosis of IgG4-RP is often challenging. We report a rare case of IgG4-RP in a 78-year-old woman presenting with complete paraplegia, sensory loss in the lower extremities, and bladder and rectal dysfunction. Gadolinium-enhanced magnetic resonance imaging showed enhancing spinal epidural lesions. A histopathological examination revealed dense lymphocyte and plasma-cell infiltration with fibrosis and increased IgG4-positive plasma cells, leading to the diagnosis of IgG4-RP. Although the serum IgG4 concentration was within the reference range, retrospective analysis of cerebrospinal fluid (CSF) showed a markedly elevated IgG4 concentration, with an increased IgG4 index and IgG4Loc. Glucocorticoid therapy resulted in radiological and neurological improvement. This case highlights the importance of considering IgG4-RP in patients with spinal HP even if serum IgG4 concentration is not elevated. Furthermore, CSF IgG4 measurement may contribute to the diagnosis of IgG4-RP, although further studies are required to establish its clinical utility.