Guide to systemic mastocytosis



Criteria for diagnosis: at least 1 major and 1 minor or 3 minor criteria present

Major:

 • Multifocal dense infiltrates of MC (2 15 MCs in aggregates) in BM or other tissues.

Minor:

 • >25% of all MCs are atypical on BM aspirate or spindle shaped on tissue sections

 • KIT mutation at codon 816

 • MCs express CD2 and/or CD25

 • Serum tryptase level >20 ng/mL (unless an AHN is present)



B- and C-Findings:

B-findings: mediator release

 • MCs in BM >30% and serum tryptase > 200 ng/ml

 • Hypercellular BM + dysmyelopoiesis, w/o cytopenias or meeting criteria for MDS or MPN

 • Organomegaly without organ dysfunction

C-Findings: possible tissue damage

 • Cytopenia (ANC<1000, Hb <10, Plt < 100k)

 • Hepatomegaly with ascites/impaired liver function

 • Palpable splenomegaly with hypersplenism

 • Malabsorption with hypoalbuminemia

 • Skeletal lesions



Dr. Laura Brown @lauraebrown



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