A 65-year-old female presents for further evaluation secondary to persistent bleeding, fatigue, and easy bruising.
The peripheral blood smear shows medium to large size hypergranular leukocytes with multiple Auer rods. Occasional giant platelets and hypogranular forms are present.
Virtual Peripheral Smear
Peripheral Blood Slide
Acute Promyelocytic leukemia (APL M3)
The patient presented with bleeding, anemia, thrombocytopenia, coagulation abnormalities, and the presence of multiple Auer rods. FISH t(15;17) cytogenetic testing was positive and confirmed a diagnosis of hypergranular APL.
Acute Promyelocytic Leukemia (APL or APML) is a subtype of Acute Myeloid Leukemia (AML) characterized by abnormal proliferation of promyelocytic cells in the peripheral blood and bone marrow, along with coagulopathy and thrombocytopenia. Patients usually experience anemia, shortness of breath, pancytopenia, fever, and bleeding. Initial diagnosis is made with morphology and/or flow cytometry and is confirmed by FISH and cytogenetic studies. The risk of rapid hemolysis makes early treatment with retinoic acid extremely important.
APL characteristically presents with a genetic abnormality present in ~ 90% of cases, a reciprocal translocation between chromosomes 15 and 17 (i.e., t(15:17)). This translocation results in the fusion of promyelocytic leukemia (PML) and the retinoic acid receptor alpha (RARA) protein.
Laboratory Testing: Coagulation - Increase in fibrin degradation products (FDP), low fibrinogen, and high PT/INR, PTT, DD, and TT. Chemistry test are often normal. Hemogram - WBC count is variable, anemia and thrombocytopenia is common. Flow Cytometry - Positive CD13, CD33, and 117 as well as absence/minimum presence of CD11a, CD18, CD66b, and negative for CD34 and HLA-DR.