Viruses produce thrombocytopenia by various mechanisms like impaired platelet production as a result of direct viral invasion, toxic effect of viral proteins on thrombopoiesis, virus-induced
hemophagocytosis and increased platelet destruction by binding of virus-induced autoantibodies or viral antigen-antibody complexes.
However, bone marrow biopsy did not show
hemophagocytosis or relapsing leukemia; therapy was started with biweekly etoposide and high-dose dexamethasone with some improvement of her fever.
The residual lymph node showed reactive germinal centers and tingible body macrophages, but no
hemophagocytosis (Figure 1).
Peripheral blood smear and bone marrow aspiration were normal in terms of
hemophagocytosis.
Microscopically, it is characterized by anastomosing and cyst-like vascular channels with papillary projections lined by sloughed plump endothelial cells often showing
hemophagocytosis.
The diagnosis may be established genetically (based on mutations of the genes loci PRF1, UNC13D, or STX11) or by fulfillment of 5 out of 8 criteria: fever; splenomegaly; cytopenia; hypertriglyceridemia; hypofibrinogenemia;
hemophagocytosis in the bone marrow, spleen, or lymph nodes; low or absent natural killer cell activity; and an elevated ferritin level (>500 ng/mL).
Hemophagocytic lymphohistiocytosis (HLH) is a condition characterized by fever, pancytopenia, hyperferritinemia, hypertriglyceridemia and
hemophagocytosis in the bone marrow (5).
Histiocytic
hemophagocytosis in miliary tuberculosis.
Histologic examination of bone marrow showed many activated macrophages, including some with
hemophagocytosis (online Technical Appendix, http://wwwnc.
Indeed, occult HLH is often present and, although it was clinically and biologically ruled out in the case presented here, it is possible that bone marrow examination would have provided evidence of
hemophagocytosis (maybe explaining anemia and increased lactate dehydrogenase).
Hemophagocytosis, plasmacytosis, caseous necrosis, and granulomas can be observed in bone marrow of patients with tuberculosis.
6%,
hemophagocytosis in bone marrow in 83%, HLH was diagnosed in one patient with Chedik - Higashi syndrome, in one patient with malaria, in one patient with typhoid fever and in one case with systemic juvenile idiopathic arthritis (sJIA).
