[1317] IgG4-Related Disease Is a Rare Cause of Recurrent Mastoiditis and Can Be Mimicked by Severe Otitis Media

Nicholas A Zane, Stefan Kraft, William Faquin, John H Stone, Vikram Deshpande. Massachusetts General Hospital, Boston, MA

Background: IgG4-related disease (IgG4-RD) is a recently recognized entity that causes progressive fibrosis and formation of mass lesions. It may present as a single focus or widespread disease in multiple sites, including in the head and neck where it has been shown to involve salivary glands, and lacrimal glands, among others. IgG4-RD can be diagnosed histologically by its hallmarks of storiform fibrosis, prominent lymphoplasmacytic (LPC) infiltrate, and obliterative phlebitis, as well as elevated serum IgG4. However, infections have been reported to elicit a histologic response that may mimic IgG4-RD. Our group recently reported a case of IgG4-related mastoiditis. We sought to elucidate the frequency of IgG4-RD as a previously-unrecognized cause of mastoiditis.
Design: We searched the pathology archives for all cases of mastoiditis between 2008 and 2011 and identified 162 cases of chronic otitis media (OM), and received in consult one case with histologic features of IgG4-RD. These were assessed for histologic evidence of IgG4-RD, and immunohistochemistry (IHC) was performed in cases with characteristic histologic findings.
Results: We identified 9 institutional cases with the histologic appearance of IgG4-RD, two of which were positive for IgG4+ plasma cells via IHC. The other 7 showed rare IgG4 positive plasma cells (<10/ HPF). Case #1 was a 33yr old male with recurrent otitis media episodes that resolved with antibiotics. A mastoid MRI showed possible cholesteatoma and he was found intraoperatively to have extensive granulation tissue surrounding the ossicles. Histology and IHC showed granulation tissue with an extensive polyclonal LPC infiltrate with 113 IgG4+ cells/hpf. Case #2 was a 68yr old male who suffered acute delirium and CT findings of coalescent mastoiditis and an osteopenic skull base, concerning for mastoiditis leading to meningitis. Intraoperative cultures grew S. pneumonia. Histology and IHC showed extensive fibrosis and a LPC infiltrate with 88 IgG4+ cells/hpf. Both cases are felt to represent chronic infection. The consultation case, diagnosed with IgG4-related mastoiditis, was a 50yr old female with 9 years of culture-negative serous OM, causing cerebritis and forming a progressive mass-like lesion requiring surgical excision. Histology & IHC showed storiform fibrosis and LPC infiltrate with >300 IgG4+ cells/hpf.
Conclusions: Our results show that IgG4-RD is an extremely rare cause of recurrent mastoiditis/OM, and severe infection may show histologic and IHC features that mimic IgG4-RD.
Category: Head & Neck

Tuesday, March 5, 2013 9:30 AM

Poster Session III # 156, Tuesday Morning


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