A 50 year old woman complains of intermittent low grade fever for 6 weeks, in association with fatigue, night sweats, loss of appetite and loss of weight. Close questioning reveals progressive distention of her abdomen for the past 6 months. She is otherwise asymptomatic. She has lived in the United States for her entire life, and has never traveled abroad.
WBC: 140,000/mm3 (4,600-11,000) Hb: 6.5 mg/dL (11-18) MCV: 84.1 (75-95) MCH: 24.7 (24-32) Plt: 34,000/mm3 (150,000-450,000) The peripheral smear reveals a normochromic normocytic anemia, and thrombocytopenia. Leukocytes are markedly increased, with 20% myeloblasts, 20% promyelocytes, 30% lymphocytes, 20% mature neutrophils, and 4% stab forms.
The ultrasound scan confirms the presence of hepatosplenomegaly. No free fluid is present.
Bone marrow studies reveal a hypercellular marrow. Erythroid series are normal, but megakaryocytes are reduced. Myeloid series are markedly increased with 45% myeloblasts, 30% promyelocytes,12% mature neutrophils, 2% lymphoblasts, and 2% stab forms. The myeloid:erythroid ratio is 9:1. Flow cytometry reveals the presence of myeloid blasts. Cytogenetic studies of the marrow cells reveal reciprocal translocation of 22q to the lower arm of 9 and 9q.
Both thin and thick smears are negative for malaria parasites