Retroperitoneal disorders associated with IgG4-related autoimmune pancreatitis

Figure 1 Histological findings with core needle biopsy: Fibrosis and inflammatory reaction with dense infiltration of abundant lymphocytes and plasma cells. A: Low magnification; B: High magnification.

Figure 2 Immunopathological findings: infiltrating cells represent lymphocytes and IgG4-positive plasma cells. A: IgG4 staining; B: IgM staining.

Figure 3 Localized pseudotumors (arrows) in a 67-year-old man with IgG4-related retroperitoneal fibrosis and autoimmune pancreatitis. A: Contrast-enhanced CT; B: T1-weighted; C: T2-weighted; D: Contrast-enhanced MRI.

Figure 4 Pseudotumor spread in the retroperitoneum surrounding the abdominal aorta and vena cava (arrow).

Figure 5 Although a ureteral stent was correctly placed into the left renal pelvis (arrow), ipsilateral hydronephrosis did not improve in a 79-year-old woman with IgG4-related retroperitoneal fibrosis.