Characteristics and prognosis of pediatric myeloid sarcoma in the cytogenetic context of t(8;21)

Prognostic Factors of Pediatric Acute Myeloid Leukemia Patients with t(8;21) (q22;q22): A Single-Center Retrospective Study

This retrospective study aimed to analyze the treatment effect and prognostic factors of pediatric acute myeloid leukemia (AML) patients with t(8;21). A total of 268 newly diagnosed pediatric AML (pAML) enrolled from 1 January 2005 to 31 December 2022 were retrospectively reviewed, and 50 (18.7%) patients harbored t(8;21) translocation. CR rate, OS, EFS, and RFS were assessed by multivariate Logistic and Cox regression models in these patients. Of the 50 patients, 2 patients abandoned treatment during the first induction course. Of the remaining 48 patients who received double-induction therapy and were included in the final analyses, CR1 and CR2 were 75.0% (36/48) and 95.8% (46/48), respectively. The overall three-year OS, EFS, and RFS were 68.4% (95% CI, 55.0-85.1), 64.2% (95% CI, 50.7-81.4), and 65.5% (95% CI, 51.9-82.8), respectively. The presence of loss of sex chromosome (LOS) at diagnosis (n = 21) was associated with a better 3-year OS [87.5% (95% CI, 72.7-100) vs. 52.7% (95% CI, 35.1-79.3), p = 0.0089], 3-year EFS [81.6% (95% CI, 64.7-100) vs. 49.7% (95% CI, 32.4-76.4), p = 0.023], and 3-year RFS [81.6% (95% CI, 64.7-100) vs. 51.7% (95% CI, 33.9-78.9), p = 0.036] than those without LOS (n = 27), and it was also an independent good prognostic factor of OS (HR, 0.08 [95% CI, 0.01-0.48], p = 0.005), EFS (HR, 0.22 [95% CI, 0.05-0.85], p = 0.029), and RFS (HR, 0.21 [95% CI, 0.05-0.90], p = 0.035). However, extramedullary leukemia (EML) featured the independent risk factors of inferior OS (HR, 10.99 [95% CI, 2.08-58.12], p = 0.005), EFS (HR, 4.75 [95% CI, 1.10-20.61], p = 0.037), and RFS (HR, 6.55 [95% CI, 1.40-30.63], p = 0.017) in pediatric individuals with t(8;21) AML. Further analysis of combining LOS with EML indicated that the EML+LOS- subgroup had significantly inferior OS (92.9%, [95% CI, 80.3-100]), EFS (86.2%, [95% CI, 70.0-100]), and RFS (86.2%, [95% CI, 80.3-100]) compared to the other three subgroups (all p < 0.001). LOS and EML are independent prognostic factors of OS, EFS, and RFS with t(8;21) pAML patients. LOS combined with EML may help improve risk stratification.

Myeloid sarcoma: An overview

Myeloid Sarcoma (MS) is a high grade, hematological malignancy defined as an extramedullary tumor mass of myeloid blasts with or without maturation that effaces tissue architecture. It is a highly heterogenous condition that represents a variety of myeloid neoplasms. This heterogeneity of MS, together with its rarity, have greatly hampered our understanding of the condition. Diagnosis requires tumor biopsy, which should be accompanied by bone marrow evaluation for medullary disease. It is presently recommended that MS be treated similar to AML. Additionally, ablative radiotherapy and novel targeted therapies may also be beneficial. Genetic profiling has identified recurrent genetic abnormalities including gene mutations associated with MS, supporting its etiology similar to AML. However, the mechanisms by which MS homes to specific organs is unclear. This review provides an overview of pathogenesis, pathological and genetic findings, treatment, and prognosis. Improving the management and outcomes of MS patients requires a better understanding of its pathogenesis and its response to various therapeutic approaches.

Pediatric Myeloid Sarcoma, More than Just a Chloroma: A Review of Clinical Presentations, Significance, and Biology

Myeloid sarcomas (MS), commonly referred to as chloromas, are extramedullary tumors of acute myeloid leukemia (AML) with varying incidence and influence on outcomes. Pediatric MS has both a higher incidence and unique clinical presentation, cytogenetic profile, and set of risk factors compared to adult patients. Optimal treatment remains undefined, yet allogeneic hematopoietic stem cell transplantation (allo-HSCT) and epigenetic reprogramming in children are potential therapies. Importantly, the biology of MS development is poorly understood; however, cell-cell interactions, epigenetic dysregulation, cytokine signaling, and angiogenesis all appear to play key roles. This review describes pediatric-specific MS literature and the current state of knowledge about the biological determinants that drive MS development. While the significance of MS remains controversial, the pediatric experience provides an opportunity to investigate mechanisms of disease development to improve patient outcomes. This brings the hope of better understanding MS as a distinct disease entity deserving directed therapeutic approaches.

Incidence, clinical characteristics, and prognostic nomograms for patients with myeloid sarcoma: A SEER-based study

Background

Myeloid sarcoma (MS) is a rare hematological tumor that presents with extramedullary tumor masses comprising myeloid blasts. A controversial issue is whether MS involving normal hematopoietic sites (liver, spleen, and lymph nodes) should be excluded in future studies. We aimed to compare MS characteristics and outcomes involving hematopoietic and non-hematopoietic sites and construct a prognostic nomogram exclusively for the latter.

Methods

Data from patients diagnosed with MS between 2000 and 2018 were collected from the Surveillance, Epidemiology, and End Results (SEER) database. According to the primary site, patients were classified as having MS involving hematopoietic sites (hMS) or non-hematopoietic sites (eMS). Clinical characteristics and survival outcomes were compared between the two groups using Wilcoxon, chi-square, and log-rank tests. Cox regression analysis was used to identify eMS prognostic factors to establish prognostic nomograms. The models’ efficiency and value were assessed using receiver operating characteristic (ROC) curves, calibration curves, and decision curve analysis (DCA).

Results

In total, 694 patients were enrolled, including 86 with hMS and 608 with eMS. There were no sex, race or marital status distribution differences between the two groups. Patients with eMS had better overall and cancer-specific survival rates than those with hMS. Additionally, prognostic factor effects differed between the two groups. Patients with eMS were randomly divided into the training (number of patiens, n=425) and validation cohorts (n=183). Age, first primary tumor, primary site, and chemotherapy were used to establish nomograms. The C-index values of overall survival (OS) and cancer-specific survival (CSS) nomograms were 0.733 (validation: 0.728) and 0.722 (validation: 0.717), respectively. Moreover, ROC, calibration curves, and DCA confirmed our models’ good discrimination and calibration ability and potential clinical utility value.

Conclusion

Our study described the differences between patients with eMS and those with hMS. Moreover, we developed novel nomograms based on clinical and therapeutic factors to predict patients with eMS’ 1-, 3- and 5-year survival rates.

Clinical characteristics, treatment, and prognosis of 118 cases of myeloid sarcoma

Myeloid sarcoma is a rare manifestation of acute myeloid leukemia (AML) and is associated with poor overall survival (OS). The optimal treatment remains unclear. The study retrospectively evaluated 118 patients with myeloid sarcoma who were treated at the First Affiliated Hospital of Zhengzhou University from January 2010 to July 2021. All cases were diagnosed by tissue biopsy. 41 patients underwent genetic mutation analysis. The most frequent genetic mutations were KIT (16.6%), followed by TET2 (14.6%), and NRAS (14.6%). The median survival time of 118 patients was 4 months (range, 1–51 months), while the median survival time of 11 patients who received allogeneic hematopoietic stem cell transplantation (allo-HSCT) was 19 months (range, 8–51 months). 4 (36.4%) of the 11 patients experienced relapse within 1 year after transplantation. 1 patient died from a severe infection. Of the 6 surviving patients, 5 patients have received maintenance treatment with decitabine after transplantation, and all remained in a state of recurrence-free survival. Patients with myeloid sarcoma have a very unfavorable outcome. Allo-HSCT is an effective treatment option. Recurrence remains the main cause of transplant failure. Maintenance treatment with decitabine after transplantation can prolong the recurrence-free survival time, although these results must be verified in a study with expanded sample size.

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

PURPOSE

Myeloid 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.

METHODS

A retrospective, single-center, case series study of eleven children diagnosed with MS by pathology was performed.

RESULTS

The 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%.

CONCLUSIONS

MS 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.