A 32-year-old man presented at the hematology department with bilateral testicular enlargement and multiple, painless, purple cutaneous nodules on both upper extremities and the trunk (Figure 1). He had been diagnosed with acute promyelocytic leukemia (APL) 7 years earlier.Complete remission was achieved with all-transretinoic acid (ATRA) and idarubicine therapy, and maintenance therapy had continued for 2 years since remission.Complete blood count and biochemical test results were normal, and peripheral blood smear (PBS) revealed no specific features. Bone marrow biopsy was performed, and did not demonstrate any leukemic infiltration. Real time polymerase chain reaction (RT-PCR) assay to detect t (15;17) (PML-RAR alpha) in blood samples was negative. Skin biopsy, however, revealed acute myeloid leukemic infiltration. Skin sample evaluated using RT-PCR for t (15;17) was positive. Bilateral, heterogeneous, hypervascular, irregular limited area was detected with testicular ultrasonography, indicative of testicular infiltration. Two weeks after confirmation of diagnosis, increase in D-dimer (>5000 μ/mL) and hypofibrinogenemia had developed. At the start of induction therapy, idarubicin (12 mg/m 2 /day, D2, 4, 6, 8), ATRA (45mg/m 2 ), arsenic trioxide (ATO) (0.15 mg/kg/day for 22 days) was administered and methylprednisolone was added for ATRA syndrome prophylaxis. On the 20 th day of therapy, after observing leukocytosis in his blood count, PBS and flow cytometry were reperformed. PBS demonstrated promyelocytes, and flow cytometry showed cell population CD13, CD33 positive, CD14 dim positive, and CD34 and HLA-DR negative. On the 30 th day of therapy, ATRA and ATO therapy was interrupted due to respiratory distress, prolonged QT, and fever. Dexamethasone 20 mg/day and intravenous imipenem 2 g/day was initiated for differentiation syndrome and pneumonia. Bilateral, subpleural consolidation areas; peribronchovascular infiltration; and ground glass opacity in the right middle lung zone was seen on tho-