1. Clinical case Daniel Martinez Hernandez Hospital Clínic, Barcelona

2. Clinical case 60 year-old man Past medical history: – Without history of allergies, anaphylaxis or syncope September 2006: – Department of Dermatology – Skin lesions: Facial erythema and pruritus Initial biopsy: rosacea June 2009: – Progression of the skin lesions: chest and limbs – Without B symptoms, lymphadenopathy, organomegaly, or diarrhea

3. Blood count Hematocrit (0.36-0.51 L/L)0.45 Hemoglobin (120-170 g/L)147 Leukocytes (4-11 x 10 9 /L) Neutrophils (2.5-7.0 x 10 9 /L) Lymphocytes (0.9-5.0 x 10 9 /L) Monocytes (0.1-1 x 10 9 /L) Eosinophils (0.0-0.5 x 10 9 /L) 7.70 5.10 1.80 0.60 0.20 Platelets (130-400 x 10 9 /L)218 Biochemistry Creatinine (0.3-1.2 mg/dL)1.01 LDH (250-450 U/L)328 Uric acid (1.9-7.4 mg/dL)6.5 Na (135-145 mEq/L)138 K (3.5-5.5 mEq/L)5.0 ASAT (5-40 UI/L)21 ALAT (5-40 UI/L)20 Tryptase (0-13 ng/mL)143 Serum protein Total protein (63-80 g/L)79 Albumin (34-58 g/L)44 Coagulation PT (80-100%)100 PTT (25-33 sec)27 sec Laboratory tests

4. 3% of mastocytes, with atypic morphology BONE MARROW SMEAR 0.33% mastocytes: CD117+++, CD45++, CD34-, FcERI+++ Aberrant expression: CD25++, CD2+ dim, CD63++/+++, CD69++het IMMUNOPHENOTYPE BM (Salamanca) Real-time qPCR assay: positive for KIT D816V mutation Positive: mastocytes, CD34+ cells, eosinophils, monocytes and granulocytes Negative: T-lymphocytes MOLECULAR BIOLOGY BM

5. DIAGNOSIS Indolent systemic mastocytosis TREATMENT Antihistamines

6. June 2012 Skin lesions : more dissemination and increased pruritus Serum tryptase: 250 ng/mL Inadequately control with antihistamines Osteopenia April 2014 UVB phototherapy (10 sessions) Poor tolerance and without response Serum tryptase: 245 ng/mL February 2015 Evolution Progression of skin lesions without other symptoms Serum tryptase: 343 ng/mL Omalizumab 150 mg/15d Poor tolerance with partial response

7. Evolution June - October 2015 – Constitutional symptoms: febricula, astenia, anorexia, weight loss (9 Kg), and diarrhea (5-6/day) – Physical examination: More and confluent skin lesions Hepatomegaly and splenomegaly (10 cm) Inguinal lymphadenopathy – CT scan Hepatomegaly and splenomegaly Left pleural effusion Inguinal lymphadenopathy Lytic bone lesions (sacrum, iliac, vertebrae, ribs and humerus)

9. Blood count Hematocrit (0.36-0.51 L/L)0.39 Hemoglobin (120-170 g/L)126 Leukocytes (4-11 x 10 9 /L) Neutrophils (2.5-7.0 x 10 9 /L) Lymphocytes (0.9-5.0 x 10 9 /L) Monocytes (0.1-1 x 10 9 /L) Eosinophils (0.0-0.5 x 10 9 /L) 15.54 11.2 2.2 1.2 0.7 Platelets (130-400 x 10 9 /L)237 Biochemistry Creatinine (0.3-1.2 mg/dL)1.96 LDH (250-450 U/L)173 Uric acid (1.9-7.4 mg/dL)7.6 Na (135-145 mEq/L)141 K (3.5-5.5 mEq/L)4.8 ASAT (5-40 UI/L)9 ALAT (5-40 UI/L)10 Tryptase (0-13 ng/mL)375 Serum protein Total protein (63-80 g/L)79 Albumin (34-58 g/L)42  2-microglobuline (0.1-2.2 mg/L) 8.9 Coagulation PT (80-100%)61.6 PTT (25-33 sec)40 sec Laboratory tests

10. BONE MARROW SMEAR

16. Mastocytes: 1.5% with atypic phenotype: CD117+++, CD203++, CD2+, CD25++ Immunophenotype (Bone marrow) 1.6% T-cells Abnormal mast cells Normal mast cells

17. BONE MARROW BIOPSY

20. CD117 CD2 CD25

21. CD3 CD20

22. Reticulin Masson’s trichrome

23. CD30

24. WT D816V KIT WT CT WT KIT 25.44 CT D816V KIT29.66 ΔCT 4.22 POSITIVE D816V KIT BONE MARROW CT WT KIT 22.72 CT D816V KIT25.82 ΔCT 3.1 POSITIVE D816V KIT PERIPHERAL BLOOD Molecular Biology (BM & PB)

25. MASTOCYTES 59 % CD34+ 39 % GRANULOCYTES 91% MONOCYTES 56% ΔCT 2.11 ΔCT 2.61 ΔCT 2.95 ΔCT 2.63 Populations isolated from bone marrow

26. D816V KIT WT CT WT KIT 22.72 CT D816V KIT25.82 ΔCT 3.1 PERIPHERAL BLOOD GRANULOCYTES 98% ΔCT 3.01 T LYMPHOCYTES 97% ΔCT 7.624 Molecular biology (BM & PB)

27. Agressive systemic mastocytosis Diagnosis Cladribine: 4 mg/d/5d (50% CKD) Nov 2015, first cycle Primary prophylaxis (P. jirovecii): cotrimoxazol Allopurinol and sodium chromoglycate Treatment Evolution

28.  History of indolent mastocytosis with detection of multilineage c-kit mutation.  Evolution to an aggressive systemic mastocytosis Summary