진단 시 낮은 종양 분율에 의해 유전 검사 위음성을 보인 급성 백혈병 1예: 최신 진단 기준에 비춘 시사점

Abstract

The accurate detection of genetic mutations is very important in acute leukemia. Occasionally, tumor fraction may not be high at diagnosis, thus leading to false negative genetic test results. We present a case of acute lymphoblastic leukemia with relapse where the percentage of blasts in bone marrow aspirate was only 7.1% at the initial diagnosis. Karyotyping and next-generation sequencing results appeared negative at diagnosis; however, a retrospective review of the initial tests revealed that some of the mutations detected later at relapse were present even at the initial diagnosis but at very low fractions. Given the recently revised World Health Organization classification (fifth edition) and International Consensus Classification, the probability of encountering acute leukemia with a low blast percentage in bone marrow is expected to increase. This case indicates that efforts should be made to reduce false negative assessments for low tumor fraction leukemia to obtain a more accurate diagnosis and improve treatment.