Table 2 B and C findings in SM

B ‘Burden of disease’ findings^a

- Bone marrow biopsy showing > 30% infiltration by MCs and serum tryptase level > 20 ng/ml

- Myeloproliferation or signs of dysplasia in non–MC lineage(s), no prominent cytopenias; criteria for AHN not met

- Hepatomegaly and/or splenomegaly without impairment of organ function and/or lymphadenopathy on palpation/imaging (>  2 cm)

C ‘Cytoreductive therapy requiring’ findings^b

- Cytopenia(s): ANC < 1000/μL, Hb < 10 g/dL, or platelets < 100,000/μL

- Hepatomegaly with impairment of liver function, ascites, and/or portal hypertension

- Palpable splenomegaly with hypersplenism

- Hepatomegaly with hypoalbuminemia and weight loss from gastrointestinal tract MC infiltrates

- Skeletal lesions: osteolyses and/or pathologic fractures

- Life-threatening organ dysfunction caused by mast cell infiltration