Figure 2
From: Macrophage activation syndrome in a patient with pulmonary inflammatory myofibroblastic tumour
Routine and immunohistochemical stainings of biopsies from cubital veins and bone marrow. ( A- B) Biopsies of cubital veins showed complete loss of normal vein architecture with massive infiltration of lymphocytes (arrows in A), histiocytes (arrows in B), macrophages and fibroblasts. ( C- D) Further immunohistochemical analysis revealed massively increased numbers of proliferating Ki-67+/CD68+ macrophages (arrows in C and D). ( E- G) Bone marrow biopsies of the patient revealed haemophagocytosis, the defining criterion of MAS. Characteristically, the histiocytes showed degenerated and nucleated proerythoblasts within their cytoplasm (arrows E- G).