Migle Janeliuniene, MD, PhD Lithuania Teaching/research/clinical Associate, Specialist Vilnius University Hospital Santariskiu Klinikos Santariskiu 2 LT Vilnius, Lithuania Phone: : 2:

Migle Janeliuniene, MD, PhD Vilnius University Hospital Salzburg medical seminars Oncology A: Hematologic malignancies June 21 – 27 Case report: systemic mastocytosis with associated clonal hematologic non-mast cell lineage disease

Patient data Female, 38 y.o., previously healthy, no chronic diseases, has 1 healthy child, 2 siblings (1 HLA matched). January 2015 routine blood test: mild thrombocytopenia February 2015: sinusitis, fatigue. Blood test repeated: PLT 113 x 10e9/l, Hgb 131 g/l, WBC 2,6 x 10e9/l. March 2015: constant fatigue, sweating, weight loss (100 kg to 85 kg), bruising, profound menorrhagia. Blood test: PLT 27 x 10e9/l, Hgb 92 g/l, WBC 5,0 x 10e9/l (12 % blasts). Hospitalized to the department of hematology. Physical examination: no skin lesions, no hepatosplenomegaly, no lymphadenopathy. ABP 110/70 mmHg, pulse rate 110 x/min, breathing 16 x/min, spO2 99%.

Laboratory examination Bone marrow aspirate: Hypercellular bone marrow with expanded erythropoiesis (53% of karyocytes), blasts constitute 23% of non-erythroid cells, myelopoesis depressed and with features of dysplasia, megakaryopoesis without significant pathology, some hypergranular myeloid cells found but their identification is difficult because of lysis. Flow cytometry: Blasts constitute ~10,3 % of BM cells (20,7% of non-erythroid cells). Blast phenotype: CD45+ dim, CD34+, CD38+, CD117+, HLA-DR+, CD13+, CD33+, CD11c+ het, MPO+, CD2-, CD7-, CD19-, CD56-. Myeloid origin confirmed. 1,3 % of BM cells have another phenotype: CD45+ dim, CD117+, CD33+, CD2+, CD25+,CD34-. These can be mast cells with aberrant phenotype.

Laboratory examination (2) Bone marrow trephine biopsy: 60 % of spindle shaped mast cells Increased amount of hematopoietic precursors Genetic testing cKIT17 D816V mutation (~10 %) No molecular AML markers (RUNX1-RUNX1T1, CBFB-MYH11, PML-RARA, MLLT3/MLL, DEK-NUP214, RPN1-EVI1, RBM15- MKL1, NMP1, CEBPA) FINAL DIAGNOSIS: systemic mastocytosis with associated clonal hematologic non-mast cell disease (acute erythroid leukemia)

Treatment and follow up 7+3 AML treatment protocol On day20: 4% of mastocytes, 62% of erythrokaryocytes and 21% of myeloid blasts in BM (resistant disease) Salvage therapy with IDA-FLAG protocol At the end of protocol: normocellular BM, blasts <1 %, erythropoiesis depressed, granulopoeisis expanded with dysplastic features (gigantic forms), flow cytometry: 0,27 % aberrant mastocytes and 0,91 % myeloid blasts (no phenotypic aberrations for minimal residual disease monitoring). Pulmonary infection as a side effect of IDA-FLAG, influenza B virus identified and managed with Oseltamivirum. Sepsis as a result of central venal catheterization (Vancomycin, CVC removed, then Meropenem). Fever reduced, CRB normalized. Patient is in clinical remission, has a HLA matched sibling and is being prepared for allogeneic BM transplantation.

Bone marrow aspirate moprhology

Flow cytometry

WHO criteria for systemic mastocytosis Major Multifocal, dense aggregates of mast cells (15 or more) detected in sections of bone marrow and confirmed by tryptase immunohistochemistry or other special stains. Minor In biopsy section, more than 25% of the masts cells in the infiltrate have atypical morphology, or, of all the mast cells in the aspirate smear, more than 25% are immature or atypical. Mast cells co-express CD117 with CD2 and/or CD25. Detection of KIT point mutation at codon 816 in bone marrow, blood, or other extracutaneous organs. Serum total tryptase persistently >20 ng/ml (not a valid criteria in cases of systemic mastocytosis with associated clonal hematologic non-mast-cell lineage disease). Diagnosis may be rendered if one major plus one minor or three minor criteria are fulfilled. Swerdlow SH, Campo E, Harris NL, Jaffe ES, Pileri SA, Stein H, Thiele J, Vardiman JW (Eds.). WHO classification of tumours of haematopoietic and lymphoid tissues. IARC: Lyon 2008, p. 54–63.