Table 3.

B- and C-findings by the 2022 ICC and the 5th WHO (Modified) [9,10,49].

	2022 ICC [9]	WHO 5th Edition [10,49]
B-findings	High MC burden (>30% of BM cellularity by MC aggregates, as assessed on BM biopsy) and serum tryptase >200 ng/mL.	High MC burden: Infiltration grade (MC) in BM ≥30% in histology (IHC) and/or serum tryptase ≥200 ng/mL and/or KIT D816V VAF ≥10% in BM or PB leukocytes.
	Cytopenia (not meeting criteria for C findings) or -cytosis. Reactive causes are excluded, and criteria for other myeloid neoplasms are not met.	Signs of myeloproliferative and/or myelodysplasia: hypercellular BM with loss of fat cells and prominent myelopoiesis ± left shift and eosinophilia ± leukocytosis and eosinophilia and/or discrete signs of myelodysplasia (<10% neutrophils, erythrocytes, and megakaryocytes).
	Hepatomegaly without impairment of liver function, or splenomegaly without features of hypersplenism including thrombocytopenia, and/or lymphadenopathy (>1 cm size) on palpation or imaging.	Organomegaly: palpable hepatomegaly without ascites or other signs of organ damage and/or palpable splenomegaly without hypersplenism and without weight loss and/or palpable lymphadenopathy or visceral lymph node enlargement found by imaging (>2 cm).
C-findings *	BM dysfunction manifested by one or more cytopenia(s): ANC <1 × 109/L, Hb <10 g/dL, PLT <100 × 109/L, but no obvious non-MC hematopoietic malignancy.	One or more cytopenia(s): ANC <1 × 109/L, Hb <10 g/dL, or PLT <100 × 109/L.
	Palpable hepatomegaly with impairment of liver function, ascites and/or portal hypertension.	Hepatopathy: ascites and elevated liver enzymes ± hepatomegaly or cirrhotic liver ± portal hypertension.
	Palpable splenomegaly with hypersplenism.	Spleen: Palpable splenomegaly with hypersplenism ± weight loss ± hypalbuminemia
	Malabsorption with weight loss due to GI MC infiltrates.	GI tract: malabsorption with hypoalbuminemia ± weight loss.
	Skeletal involvement with large osteolytic lesions and/or pathological fractures.	Bone: large-sized osteolysis (≥2 cm) with pathologic fracture ± bone pain.

* C-findings in 2022 ICC has no changes, adopted from prior 2016 WHO classification [7]. ANC, absolute neutrophil count; BM, bone marrow; Hb, hemoglobin; PB, peripheral blood; PLT, platelets.