A retroperitoneal mass around the left internal iliac artery. A: Fibrotic nodules approximately 2 cm in diameter are seen. B: Fibrosis and dense inflammatory cells are patchily distributed around the peripheral nerves, and obliterative phlebitis is seen. C: At high magnification, infiltrates of plasma cells and eosinophils are seen.
Fujii et al. Diagnostic Pathology 2014 9:41 doi:10.1186/1746-1596-9-41