Erythroblastic Sarcoma in Adults and Children: Different Pathways to the Same Destination

Area of Science:

• Hematology
• Oncology
• Pathology

Background:

• Erythroblastic sarcoma (ES) is a rare, mass-forming variant of acute erythroid leukemia.
• Limited data exists on its diagnostic criteria, immunophenotype, and molecular features.

Purpose of the Study:

• To describe the clinicopathologic, immunophenotypic, and molecular characteristics of adult and pediatric Erythroblastic Sarcoma.
• To compare features between adult and pediatric ES to understand potential differences in pathogenesis.

Main Methods:

• Retrospective analysis of 56 Erythroblastic Sarcoma cases (36 adult, 20 pediatric).
• Morphologic, immunophenotypic (including CD71, GLUT1, CD43, E-cadherin, CD117, CD45, P53), cytogenetic, and molecular (TP53 mutations, gene fusions) analyses were performed.
• Clinical data including prior therapy, myeloid neoplasm history, site of involvement, and outcomes were collected.

Main Results:

• Adult ES showed associations with prior cytotoxic therapy and myeloid neoplasms, with bone involvement common. Pediatric ES showed soft tissue or CNS involvement.
• Immunophenotypically, both groups showed erythroblast markers (CD71, GLUT1) and CD43, E-cadherin, CD117 positivity, with CD45 negativity.
• Adult ES frequently had TP53 mutations (often biallelic), while pediatric ES was enriched for gene fusions, notably involving NFIA.
• Prognosis was poor for both groups, with a median overall survival of 3 months.

Conclusions:

• Adult and pediatric Erythroblastic Sarcoma share overlapping morphologic and immunophenotypic features.
• Distinct molecular profiles (TP53 mutations in adults, gene fusions in children) suggest diverging pathogenetic mechanisms.
• ES has a poor prognosis regardless of age, highlighting the need for further research and targeted therapies.