Clinical characteristics, pathology features and outcomes of pediatric myeloid sarcoma: A retrospective case series

Abstract

PurposeMyeloid sarcoma (MS) is a rare extramedullary mass with myeloid expression, which is easy to be missed and misdiagnosed, especially in the pediatric population. We analyze the clinicopathological characteristics, immunophenotypic, cytogenetic, and molecular studies, therapeutic approaches, and outcomes, to optimize the management of such patients.MethodsA retrospective, single-center, case series study of eleven children diagnosed with MS by pathology was performed.ResultsThe male-to-female ratio was 8:3, and the median age at diagnosis was 7 years. The most commonly involved sites were the skin and orbital region, followed by lymph nodes, central nervous system, and testis. Seven cases (64%) with Class I-MS and four cases (36%) presented as Class II-MS. Immunohistochemically, MPO and CD117 were the most commonly expressed markers, followed by CD33, CD43, CD34, CD68, and lysozyme. Chromosomal abnormalities were detected in 4 patients. Two patients had the presence of deleterious mutations (FLT3, ASXL, KIT, and DHX15) on molecular detection. Ten patients were treated with chemotherapy based on AML regimens. The median follow-up time was 33.5 months in eleven patients. Two patients relapsed, one died, and one lost to follow-up. The 2-year overall survival (OS) rate estimated by Kaplan-Meier curves was 90.9% ± 8.7%, and the event-free survival (EFS) rate was 64.9% ± 16.7%.ConclusionsMS diagnosis is usually challenging. Adequate tumor biopsy and expanded immunohistochemistry are necessary for the correct diagnosis of MS. Early and regular systemic chemotherapy promises long-term survival.

Genetic alterations in myeloid sarcoma among acute myeloid leukemia patients: insights from 37 cohort studies and a meta-analysis

“…Figure 3 presents a detailed analysis of the pooled prevalence of fusion genes in patients with MS, highlighting the frequency of various fusion genes within this group. The most predominant fusion gene observed was RUNX1::RUNX1T1, with a remarkable pooled prevalence of 28.10% (95% CI 15.10% to 41.20%; I² 96.39%; Figure 3A) (9,14,25,28,34,35,38,41,42,45,(48)(49)(50). The KMT2A:: MLLT3 fusion gene was also identified at a pooled prevalence of 19.20% (95% CI -14.60% to 53.00%; I² 79.63%; Figure 3B) (14,43).…”

“…Furthermore, we calculated the overall pooled prevalence of AML patients with MS harboring recurrent genetic abnormalities, as per the 2022 World Health Organization classification, to be 36.80% (95% CI: 26.00% to 47.60%; I² 96.85%; Supplementary Data 4) (9, 12, 14-16, 23-29, [31][32][33][34][35][36][37][38][39][40][41][42][43][45][46][47][48][49][50].…”