IgG4-related disease presenting as intradural extramedullary lesion: a case report and review of the literature.

IgG4-related disease (IgG4-RD) is a fibro-inflammatory disorder affecting various anatomical sites, and only recently was identified to affect the dura of the spine. The authors present the second reported case of an intradural extramedullary lesion consistent with IgG4-related spinal disease. A literature review was performed that identified 15 other cases of spinal disease, and common features of all known reported spinal IgG4-RD are discussed. Spinal IgG4-RD typically affects males of approximately 50 years of age, and often presents as a T1 and T2 hypo- or isointense lesion that homogenously enhances. Surgical intervention typically involves subtotal resection or biopsy, and histopathologic findings include increased IgG4-positive cells or an IgG4:IgG ratio >40%. The disease responds well to steroids early on, and treatment can include adjuvant therapy such as azathioprine. Systemic involvement is possible, and, early treatment can quickly minimize disease burden. Thus, increased suspicion would result in early diagnosis and improved prognosis.