Review Question - QID 107168

This patient has clinical findings of fatigue and pallor, laboratory findings of pancytopenia, and biopsy findings of myeloblasts with Auer rods, in keeping with a diagnosis of acute myelogenous leukemia (AML).

AML is caused by a neoplastic proliferation of myeloblasts in bone marrow. The neoplastic myeloblasts are not able to mature normally, eventually leading to crowding-out of normal hematopoeisis. AML is most commonly seen in adults in the 5th-6th decades of life. Three major subtypes of AML are acute promyelocytic leukemia (APL), acute megakaryoblastic leukemia, and acute monocytic leukemia.

Davis et al. review acute leukemia in adults. AML account for 80% of all cases of acute leukemia in adults. As compared with chronic leukemias, acute leukemias present with sudden onset symptoms and are more likely to present with significant constitutional symptoms such as fever or weight loss. Abnormal bleeding and infections are also common. Complete blood count in AML will vary depending on the subtype but generally shows pancytopenia.

Yue et al. discuss the detection of Auer rods. Auer rods, which are crystalized aggregates of myeloperoxidase, are important in the rapid diagnosis of acute promyelocytic leukemia (APL), which is a subtype of AML. The authors compared two different histological staining techniques, Wright-Giemsa stain vs. Liu's stain. The authors used both stains on cells taken from known APL patients and found a significantly higher rate of detectable Auer rods with Liu's stain, thereby suggesting Liu's stain is more sensitive for rapidly diagnosing APL.

Figure A depicts Auer rods in myeloblasts taken from a bone marrow aspirate.

Incorrect Answers:
Answer 1: Acute lymphoblastic leukemia would not have Auer rods on histology.
Answers 3-4: Chronic leukemias do not typically present with acute symptoms, as seen in this patient.
Answer 5: Multiple myeloma is a monoclonal plasma cell disorder, which usually presents in older patients (average age at diagnosis is 70).