Author response: Teaching NeuroImages: Idiopathic hypertrophic pachymeningitis

As discussed by Dr. Budhram, immunoglobulin G4 (IgG4)–related disease (RD) must be considered in patients with hypertrophic pachymeningitis (HP) as it accounts for a high proportion of cases originally thought to be idiopathic.1 IgG4-related HP is pathologically characterized by a lymphoplasmacytic infiltration of IgG4-positive plasma cells.2 The patient we presented had normal IgG4 levels in both serum and CSF.1 Dural biopsy was consistent with a chronic lymphohistiocytic pachymeningitis without substantial plasma cell infiltrate to suggest IgG4-RD. In addition, immunohistochemistry performed on the dural biopsy specimen was IgG4-negative. Our case highlights the steroid responsiveness of idiopathic HP and the excellent response to immunotherapy with methotrexate.1 We agree with Dr. Budhram that immunostaining of dural specimens should be done in patients with HP, as this may help guide treatment for steroid-refractory HP when IgG4 disease can be identified.
Source: Neurology - Category: Neurology Authors: Tags: WRITECLICK & amp;reg; EDITOR ' S CHOICE Source Type: research