Vasculitic neuropathy associated with IgG4-related kidney disease: A case report and literature review

Abstract

IgG4-related disease is an immune-mediated systemic inflammatory condition characterized by tissue infiltration of IgG4-positive plasma cells and elevated serum IgG4 concentrations. Peripheral neuropathy is an atypical manifestation of this disease. We describe an unusual case of vasculitic neuropathy in a patient with IgG4-related kidney disease. A 55-year-old woman presented with right leg weakness progressing to bilateral leg weakness, pain and numbness of the legs, and impaired gait. She was previously evaluated for weight loss and anemia with a CT scan of the abdomen due to concern for malignancy. Abnormal enhancement of the kidneys was seen, and laboratory work-up and kidney biopsy were consistent with IgG4-related disease. Myeloperoxidase-antineutrophil cytoplasmic antibodies were also positive. In combination with the patient's asymmetric leg weakness and painful neuropathy, this raised concern for vasculitis. Sural nerve biopsy confirmed vasculitic neuropathy. Recent studies have demonstrated an overlap in the clinical characteristics of IgG4-related disease and the anti-neutrophil cytoplasmic antibody-associated vasculitides, which are known to cause vasculitic neuropathy. Clinicians should recognize this association, and IgG4-related disease should be considered in the differential diagnosis in patients with peripheral neuropathy in the right clinical context.

Figure 1.. CT scan of the abdomen and kidney biopsy. A: CT scan of the abdomen with iodinated contrast showing asymmetric enlargement of the left kidney, with heterogeneous contrast enhancement and loss of normal corticomedullary differentiation bilaterally. Similar findings were present in the right kidney but to a lesser degree. B: Kidney biopsy showing focally accentuated lymphoplasmacytic inflammatory infiltrates with storiform fibrosis on hematoxylin and eosin stain at × 10 magnification, with (C) IgG4-positive plasma cells (arrowheads) highlighted on immunohistochemical staining for IgG4 on formalin-fixed paraffin-embedded tissue section at × 20 magnification.

Figure 2.. Sural nerve biopsy. A: 1-micron plastic-embedded sections showing a re-canalized vessel in the epineurium and two fascicles showing (B) severe fiber loss and (C) acellularity/fibrosis in the endoneurium. D: Fresh frozen nerve showing inflammation in the perineurium of 1 fascicle and (E) an occluded recanalized vessel with some perivascular mononuclear cells. F: Immunohistochemical staining for IgG4 showing IgG4-positive cells (arrowheads) at × 20 magnification, with (G) × 40 magnification of the same focus.