IgG4-related disease is a fibroinflammatory condition that affects many different organs. The common pathological findings of this disease include storiform fibrosis and dense infiltration of lymphocytes rich in IgG4-positive plasma cells. We herein presents the diagnosis and treatment of a case with a newly recognized condition - IgG4-related pachymeningitis.

A 69-year-old man presented with multiple spontaneous bruises in the past 2 weeks. Several large-sized hematomas were found on examination. The initial investigation revealed a prolonged activated partial thromboplastin time (aPTT) with normal platelet count and international normalized ratio. Further investigation revealed a low factor VIII activity secondary to presence of factor VIII inhibitor, making the diagnosis of acquired hemophilia A. Further work-up revealed that pernicious anemia was present and acted as an associated disease. After steroids therapy, his aPTT was normalized and the factor VIII inhibitor titer became undetectable. 2 months later, a relapse occurred and new hematomas appeared at his retropharyngeal space and left arm. His bleeding was controlled by administration of recombinant factor VIIa, and a combined therapy of intravenous steroids and rituximab was given to eradicate the inhibitor. The approach to workup of bleeding disorders as well as treatment of acquired hemophilia A are herein discussed.