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. 2004 Jun;57(6):604–608. doi: 10.1136/jcp.2003.014860

Figure 2.

Figure 2

Systemic mastocytosis with an associated clonal haematological non-mast cell lineage disease (SM-AHNMD): SM with an associated acute myeloid leukaemia (SM-AML). (A) The mast cells coexpress CD25, underlining their neoplastic nature and confirming the diagnosis of SM-AMLM1. ABC method; anti-CD25. (B) There is coexpression of the stem cell associated antigen CD34 by the myeloblasts, whereas the mast cells are negative. The immunophenotype of the blast cells is consistent with the diagnosis of AMLM1. ABC method; Qbend10 (anti-CD34). (C) Immunostaining with antimyeloperoxidase reveals strong cytoplasmic reactivity of the myeloblasts, whereas the granulomatoid mast cell infiltrates remain unstained. Note the sharp demarcation of mast cell aggregates from the surrounding diffuse leukaemic infiltrate. Avidin–biotin complex (ABC) method; antimyeloperoxidase. (D) Higher magnification reveals strong cytoplasmic reactivity of the mast cells for antitryptase. ABC method; AA1 (antitryptase).