Mast Cell Disease Case 054 Session 7

Transcription

1 Mast Cell Disease Case 054 Session 7 Rodney R. Miles, M.D., Ph.D. Lauren B. Smith, M.D. Cem Akin, M.D. Diane Roulston,, Ph.D. Charles W. Ross, M.D. Departments of Pathology and Internal Medicine University of Michigan Health System

2 Clinical presentation 28-year year-old female presented with petechiae and easy bruising Initial CBC WBC 5.0 k/mm 3 Hemoglobin 5 g/dl Platelets 3 k/mm 3

3 Initial bone marrow evaluation 86% blasts on aspirate smear Flow cytometry immunophenotyping CD33, CD117, CD56 Negative for CD34, CD19 Acute myeloid leukemia

4 Cytogenetics Final diagnosis 46,XX,t(8;21)(q22;q22) [11] 47,idem,+4,i(4)(q10) [9] Acute myeloid leukemia with t(8;21)(q22;q22)

5 Patient entered first remission Day 15 marrow hypoplastic,, no AML Day 30 marrow 60% cellular, no AML Day 150 marrow, continued remission This sample evaluated for presence of mast cells based on association between t(8;21) and C-KIT mutation Morphology Flow cytometry mast cell study Immunohistochemistry

6 Atypical mast cells on aspirate

7 Mast cell clusters in core biopsy

8 Mast cells expressed dim CD2 and dim CD25 CD117-PE CD25-FITC CD117-PE CD117-PE CD117-PE CD2-PC5 MSIGG1-PC5 MSIGG1-FITC

9 IHC on bone marrow core Mast Cell Tryptase, 400x C-KIT, 1000x

10 Patient met WHO criteria for systemic mastocytosis (SM) Major criterion Increased mast cells with clusters of >15 cells Minor criteria >25% of mast cells had atypical features Flow cytometry on aspirate detected mast cells with aberrant CD2 and CD25 Serum tryptase 256 ng/ml ( ) ** Patient lacked clinical symptoms of SM

11 Re-review of original bone marrow Bone marrow core biopsy at initial presentation

12 Perivascular cuff of mast cells Included in slide box

13 Mast cell aggregates in original bone marrow consistent with SM Tryptase stain of bone marrow at initial presentation

14 Disease course Diagnosed with relapsed AML at routine follow-up visit 8 months after initial presentation Cytogenetics: : 47,XX,+8,t(8;21)(q22;q22) [19] Post-relapse day 13 and 19 marrows showed persistent relapse of AML and persistent SM

15 Perisinusoidal mast cells Included in slide box

16 Mast cell aggregate, 1000x

17 Myleoblasts and mast cells showed distinct immunophenotypes IHC Marker Myeloblasts Mast Cells CD117 wk + ++ Tryptase - ++ CD MPO + -

18 C-KIT D816V mutation identified RNA was extracted from bone marrow cells Relapse marrow sample including leukemic blasts and mast cells, unsorted RT-PCR amplification of the region around codon 816 PCR product was digested with Hinf1 Recognizes the extra restriction site created by A>T transition Results were confirmed by sequencing

19 Repeated marrows over next 4 months: Never achieved second remission Persistent SM Disease course Underwent salvage therapy with dasatinib Patient died 15 months after initial diagnosis

20 Summary of case Patient presented with AML t(8;21)(q22;q22) Approximately 5 months after initial presentation, increased mast cells were identified in a remission marrow. Met WHO criteria for SM Retrospective analysis identified SM in original bone marrow biopsy

21 Proposed diagnosis (WHO) AML with recurrent genetic abnormality t(8;21)(q22;q22) Systemic mastocytosis SM with associated clonal,, hematological non-mast cell lineage disease (SM- AHNMD)

22 SM and C-KIT mutations affect prognosis in t(8;21) AML SM associated with worse prognosis in t(8;21) AML -Pullarkat et al., Am J Hematol 73:12-7, 7, 2003 C-KIT mutations in % of t(8;21) AML C-KIT D816 associated with worse survival in t(8;21) Schnittger et al., Blood 107:1791-9, 9, 2006 Cairoli et al., Blood 107:3463-8, 2006 Mutated C-KIT in t(8;21) associated with relapse risk, not survival Paschka et al., J Clin Oncol 24: , 2006

23 Mast cells related to leukemic clone C-KIT mutation in SM-AHNMD: SM+/AHNMD+ or SM+/AHNMD- Valent et al., Leuk Lymphoma 46:35-48, 48, 2005 Case report: in a patient with SM with t(8;21) AML, the bone marrow mast cells showed the t(8;21), proving origin from the leukemic clone Pullarkat V, et al., Leuk Res 31:261, 2007

24 Conclusion: look for mast cells in t(8;21) AML Similar to a previous case study, SM not noted in initial bone marrow study of t(8;21) AML; mast cells noted in remission Bernd et al., J Clin Pathol 57:324-8, 2004 Suggests need to evaluate for mast cells in new t(8;21) AML patients