Spontaneous Remission Of Acute Monocytic Leukemia With Trisomy 8 And Trisomy 18

Abstract

A 67-year-old male with no medical history presented with fever and visited a general practitioner.Based on the complete blood count, he had leukocytosis (white blood cell [WBC] count, 46,000/μl) and thrombocytopenia (platelet count, 29,000/μl), and was thus referred to our hospital (Day 1).His temperature ranged from 37.1°C to 37.8°C, but the physical examination results were unremarkable.No evidence of hepatosplenomegaly, gingival hypertrophy, or petechiae was found.Laboratory findings were as follows: WBC count, 33,000/μl; hemoglobin level, 11.8 g/dl; platelet count, 8000/μl; C-reactive protein level, 3.89 mg/dl; and lactate dehydrogenase level, 1,124 U/l.Serum and urine lysozyme levels were high (46.4mg/µL [normal range, 5.0-10.2]and 0.03 mg/µL [0.0], respectively).Peripheral blood contained 28% blasts, including promonocytes.Bone marrow aspiration smear revealed 55.6% blasts, including promonocytes, with monocytic differentiation; some blasts had many small vacuoles, a few large vacuoles, or honeycomb-like vacuoles in the wide cytoplasm.A few monocytes and macrophages exhibited hemophagocytosis.On cytochemical staining, 31% of blasts, including promonocytes, were positive for myeloperoxidase activity, 71% were positive for non-specific esterase reactions, and all blasts were negative for naphthol AS-D chloroacetate esterase activity.Non-specific esterase reactions were inhibited by sodium fluoride.On flow cytometry, the blasts expressed cluster of differentiation (CD) 13, CD14, CD33, and CD56; the blasts weakly expressed myeloperoxidase but were negative for CD34.Cytogenetic