Certain clinical and laboratory findings can help distinguish different types of systemic mastocytosis.



(1) mast cell involvement in bone marrow

(2) myelodysplasia and/or myeloproliferative changes

(3) hepatosplenomegaly

(4) lymphadenopathy

(5) skeletal involvement

(6) gastrointestinal involvement


"B" Findings

"C" Findings

bone marrow

> 30% mast cells, with focal, dense aggregates OR serum total tryptase level > 200 ng/mL


myelodysplasia and/or myeloproliferative changes in non-mast cell lines

present, but insufficient for definitive diagnosis of haematopoietic neoplasm; blood counts normal or only slightly abnormal

present but insufficient for definitive diagnosis of a haematopoietic neoplasm; blood counts show one or more cytopenias


palpable, but with no impairment of liver function

palpable with impaired liver function, ascites and/or portal hypertension


palpable but without hypersplenism

palpable with hypersplenism


palpable or visceral


skeletal involvement


present with osteolysis and/or pathological fractures



mast cell infiltrates with malabsorption and weight loss



• Cytopenias: hemoglobin < 10 g/dL, platelet count < 100,000 per µL, absolute neutrophil count < 1,000 per µL

• If there is evidence for a definitive diagnosis of haematopoietic neoplasm (myelodyplastic syndrome, chronic myeloproliferative syndrome, acute leukemia, malignant lymphoma, etc.), then the patient is classed as having systemic mastocytosis with associated clonal haematological non-mast cell lineage disease (SM-AHNMD).


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