A 63-year-old woman developed 3 erythematous, pruritic plaques on her left lower extremity. She called her dermatologist and was prescribed prednisone for likely contact dermatitis from poison ivy. Two weeks later, the patient developed fatigue and bruising. Findings from a complete blood cell count were abnormal, demonstrating blasts (promyelocytes predominant), anemia, and thrombocytopenia. The patient was admitted for workup.
On admission, her white blood cell count was 4500 cells/μL (normal range, 4500-11 000 cells/μL); hematocrit level was 31.4% (normal range, 35%-45%); and platelet count was 33 × 103/μL (normal range, 153 × 103/μL to 367 × 103/μL). A manual differential count demonstrated 62% promyelocytes. Analysis of bone marrow biopsy specimens showed markedly hypercellular marrow with 90% promyelocytes and a positive translocation of 15:17 on fluorescence in situ hybridization. Flow cytometry revealed cells positive for CD13, CD33, CD38, and CD117 and negative for CD14, CD64, CD2, CD11, CD3, CD20, CD7, CD34, and HLA-DR, which was consistent with acute promyelocytic anemia. Polymerase chain reaction revealed a 0.436 ratio of the PML-RAR-α oncogene in her bone marrow.
Markowski TR, Martin DB, Kao GF, Lutz L, Deng A, Gaspari AA. Leukemia Cutis: A Presenting Sign in Acute Promyelocytic Leukemia. Arch Dermatol. 2007;143(9):1209–1226. doi:10.1001/archderm.143.9.1220