Bone marrow pathologic features and differentiation of systemic mastocytosis

【Objective】To explore the pathologic features,diagnosis and differentiated diagnosis of systemic mastocytosis(SM).【Methods】 Retrospectively analyzed the bone marrow morphology,immunophenotype and special stains of 2 patients with SM.【Results】 One case was a 73-year-old man,who presented with cutaneous pruritus for 7 years and malaise for 2 months.Physical examination revealed splenomegaly but no hepatomegaly and lymphadenopathy;Another case was a 57-year-old woman,who presented with pale,malaise and fever for more than 5 months.Physical examination revealed a small amount of bleeding on her lower limbs and back.Peripheral blood examination showed one case with pancytopenia and another case with anemia and leukopenia.Bone marrow smears showed mastcytosis(15.5% and 6.5%) in both cases.Bone marrow biopsy sections revealed abnormal mast cells multifocal infiltration,interrningled with lymphocytes,eosinophils and fibroblasts.Those cells with metachromatic granules were indicated by toluidine stain.Immunohistochemical study showed abnormal cells were positive for CDll7,CD25,but negative for CD2,MPO,lysozyme,CD20 and CD3.【Conclusion】 Bone marrow findings of SM are characteristic.Bone marrow pathologic morphology,special stains and immunohistochemistry are very important to the diagnosis of SM.