IgG4-Related Disease Presenting as Recurrent Mastoiditis With Central Nervous System Involvement.

We report a case of a 43-year-old female who presented with right ear fullness and otorrhea. She was initially diagnosed with mastoiditis that was not responsive to multiple courses of antibiotics and steroids. She was then diagnosed with refractory inflammatory pseudotumor, and subsequent treatments included several mastoidectomies, further steroids, and radiation therapy. The patient went on to develop mastoiditis on the contralateral side as well as central nervous system involvement with headaches and right-sided facial paresthesias. Reexamination of the mastoid tissue revealed a significantly increased number of IgG4-positive cells, suggesting a diagnosis of IgG4-related disease. The patient improved clinically and radiographically with rituximab and was able to taper off azathioprine and prednisone. IgG4-related disease should be considered in patients with otologic symptoms and be on the differential diagnosis in patients with inflammatory pseudotumor. Staining for IgG and IgG4 is essential to ensure a prompt diagnosis and treatment.