Canterbury DHB


Diagnostic Criteria for SM

WHO 2016 diagnostic criteria for SM

SM is typically associated with dense, multifocal mast cell infiltrates of the bone marrow. Malignant mast cells often show atypia (spindle-shape) and may be hypogranular, which makes them difficult to identify in H&E sections. Special stains are necessary to identify mast cells (tryptase) and malignant mast cells (CD2 and CD25 positive).

For criteria of SM, see Valent P (2016),2 table 1.

C-kit mutation analysis is required to determine whether patients are likely to respond to imatinib. Patients with wild-type KIT, or those with other mutations (such as K509I or F522C) may be sensitive to imatinib. However, over 80% of patients with SM have a KITC816V mutation and do not respond to imatinib.

For an algorithm for diagnosing and classifying SM, see Pardanani A, Tefferi A (2010),5 figure 1.

About this Canterbury DHB document (8062):

Document Owner:

Bridgett McDiarmid (see Who's Who)

Last Reviewed:

August 2018

Next Review:

April 2021


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Topic Code: 8062