IgG4-related pachymeningitis and mastoiditis, associated with cerebral venous thrombosis: A case report.

IgG4-related disease (IgG4-RD) is a multisystem fibroinflammatory condition; this can be a challenging diagnosis that requires clinico-pathologic correlation. We report a young woman, presenting with cranial nerve palsy. The work-up revealed pachymeningitis, cerebral venous thrombosis (CVT), and a destructive lesion in the mastoid. We diagnosed IgG4-RD through mastoidectomy. Thus, a biopsy of asymptomatic, infrequently affected organs, like the mastoid, can meet all histopathological criteria. In neuro-meningeal presentations, CVT may be secondary to the local inflammatory environment of pachymeningitis. Since our patient had a deep vein thrombosis one year prior, we discuss a possible higher risk of thrombosis in IgG4-RD patients.