Fig. 6

Photomicrograph of the biopsy sample performed from the perinephric soft tissue infiltrates in a 60-year-old male patient with Erdheim–Chester disease reveals collection of histiocytes with abundant foamy cytoplasm and associated with minimal lympho-plasmacytic infiltrates on high power (100×) (A). Immunohistochemistry staining for CD-68 reveals histiocytes positive for CD-68 cells (B)