Patients with suspected BPDCN and meeting eligibility criteria will be enrolled in the study. First, BPDCN diagnosis will be confirmed by anatomic pathology (Dr Petrella T, Montreal) and cytologic plus immunophenotyping analysis (Pr Garnache Ottou F, UMR1098 BESANCON). Patients will then receive three 21 days cycles of a combination of chemotherapy (Ida/Metho/L-asp/Dex), followed by an evaluation. Patients with complete response (CR) or complete response with incomplete bone marrow recovery (CRi) will undergo an allo- or auto-SCT and those who are not eligible to the transplantation will have successive 28 days cycles of chemotherapy (Metho/L-asp/Dex). Patients who did not respond to the treatment will be treated by physicians. All patients will be followed for 24 months.

Inclusion Criteria:

• Newly diagnosed BPDCN established by a blood or bone marrow immunophenotypic diagnosis by flow cytometric and/or by the anatomic pathology study of a skin biopsy using validated diagnostic criteria (Swerdlow SH CE et al., World Health Organisation Classification of Tumors, 2008; Garnache-Ottou et al., 2009; Angelot et al., 2012; Julia et al., 2014) or patients with confirmed isolated skin lesion.
• 18 years of age or older
• No prior cytotoxic therapy except <2 week of corticosteroids or hydroxyurea
• ECOG ≤2
• Written informed consent
• Affiliation to the French social security scheme

Exclusion Criteria:

• Cardiac contra-indication to anthracyclines: cardiac dysfunction events (NYHA grade 3 or 4 and/or LVEF<50%)

• Hepatocellular abnormalities except if considered related to the BPDCN:

  1. ASAT (SGOT) and/or ALAT (SGPT) > 5 x ULN
  2. Total bilirubin ≥ 2.5 x ULN

• Creatinine level >1.5x ULN or creatinine clearance (MDRD)<50 mL/mn

• Prior thrombotic event

• Active hepatitis B or C virus infection

• HIV positive

• Serious medical or psychiatric illness that could interfere with the completion of treatment

• Known allergy to any of the study medications, their analogues, or excipients in the various formulations of any agent.

• Pregnant and lactating female patients

• Patients diagnosed with or treated for another malignancy within 2 years before study enrollment or with residual disease (basal cell carcinoma or cervical carcinoma in situ patients may be enrolled if they have undergone complete resection)