Clinical Analysis of Pediatric Acute Leukemias of Ambiguous Lineage: A Single Institution Retrospective Review

Acute leukemias of ambiguous lineage (ALAL) is a rare type of acute leukemia, referring to a group of disorders characterized by a combination of myeloid, lymphoid, or more lineages, whose incidence is significantly lower in children than adults. Here, we summarized the clinical features and outcomes of 36 pediatric ALAL patients in past 16 years. The patients diagnosed as ALAL based on the criteria of EGIL scoring system in 1998 (EGIL 1998) and/or the 2016 revisions to the WHO classification (WHO 2016) from January 1, 2005 to December 1, 2021 were included, respectively. During follow-up for a median 22 months, the median leukemia-free survival (LFS) was 18 months (0 to 172 mo) and the median overall survival (OS) was 22 months (1 to 173 mo), with a 5-year LFS rate of 67.3±9.2% and a 5-year OS rate of 66.0±10.7%. Patients who sustained negative minimal residual disease after 2 courses of standardized chemotherapy contributed to better 5-year OS (100% vs. 37.2±22.0%, P =0.028) and LFS (100% vs. 46.7±16.6%, P =0.028).