Table of Contents
Washington University Experience | MISCELLANEOUS | Idiopathic Hypertrophic Pachymeningitis (IgG4 Disease) | 2A0 Case 2 History
Case 2 History ---- The patient is a 41 year old woman who originally presented with seizures. Radiological imaging identified a lesion involving the ethmoid sinuses and frontal skull base. She underwent left paranasal sinus biopsy which was sent in consultation to this hospital. Consultation review of slides prepared from that biopsy material yielded the diagnosis: "Fibroinflammatory process suggestive of late-phase eosinophilic angiocentric fibrosis”. Subsequently, she underwent additional biopsies of the nasal cavities and paranasal sinuses in 2014, the left inferior frontal dura and brain in 2014 and the frontal dura in 2016 . Review of the dura and left meningeal specimens showed dense lympho-plasmacytic infiltrates and numerous IgG4-positive plasma cells, focal arachnoid hyperplasia and storiform fibrosis. Underlying neocortex was involved by a B cell rich lympho-plasmacytic infiltrate with focally numerous IgG4 plasma cells, leptomeningeal fibrosis and focal suspected obliterative phlebitis, astrocytosis and focal arachnoid hyperplasia. ---- The absence of clonality, cytologic atypia and significant proliferation within the lympho-plasmacytic infiltrate argue strongly against a hematolymphoid neoplasm. Further, the constellation of (1) a dense lymphoplasmacytic infiltrate, (2) widespread meningeal fibrosis (with multifocal storiform patterning), (3) examples suspicious for obliterative phlebitis, and (4) plasma cell clusters including numerous IgG4+ constituents, is highly suspicious for IgG4-related disease. It is worth noting that many diagnostic thresholds for the density or proportion of IgG4-positive plasma cells have been proposed for the broader entity of IgG4-related disease, but none have been broadly accepted – particularly for cases involving the meninges.
