Pediatric Erythroid Sarcoma Diagnostically Confirmed by Identification of a Recurrent NFIA::CBFA2T3 Fusion.

Erythroid sarcoma (ES) is exceedingly rare in the pediatric population with only a handful of reports of de novo cases, mostly occurring in the central nervous system (CNS) or orbit. It is clinically and pathologically challenging and can masquerade as a nonhematopoietic small round blue cell tumor. Clinical presentation of ES without bone marrow involvement makes diagnosis particularly difficult. We describe a 22-month-old female with ES who presented with a 2-cm mass involving the left parotid region and CNS. The presence of crush/fixation artifact from the initial biopsy made definitive classification of this highly proliferative and malignant neoplasm challenging despite an extensive immunohistochemical workup. Molecular studies including RNA-sequencing revealed a NFIA::CBFA2T3 fusion. This fusion has been identified in several cases of de novo acute erythroid leukemia (AEL) and gene expression analysis comparing this case to other AELs revealed a similar transcriptional profile. Given the diagnostically challenging nature of this tumor, clinical RNA-sequencing was essential for establishing a diagnosis.

Anelo OM ，Ma J ，Neary JL ，Koo SC ，Inaba H ，Pinto SN ，Nguyen NT ，Hoang TN ，Bui LN ，Klco JM ，Gheorghe G ，Blackburn PR ... -  《-》

Novel t(1;8)(p31.3;q21.3) NFIA-RUNX1T1 Translocation in an Infant Erythroblastic Sarcoma.

Pure erythroid leukemia (PEL) is exceptionally rare in the pediatric setting. Four pediatric PEL cases with t(1;16)(p31;q24) NFIA-CBFA2T3 were reported previously. We present a case of an infant with PEL presenting with erythroblastic sarcoma and harboring a novel t(1;8)(p31.3;q21.3) NFIA-RUNX1T1 fusion detected by RNA sequencing and conventional karyotype. Bone marrow (BM) and abdominal mass biopsies from the patient were evaluated with extensive immunohistochemical, flow cytometric, cytogenetic, and molecular studies. The patient was a female infant who presented between 2 and 5 months of age with cytopenias and an enlarging abdominal mass. Blasts in the BM and abdominal mass expressed CD71 and CD117 with focal expression of CD43, E-cadherin, epithelial membrane antigen, and hemoglobin A. They were negative for additional myeloid, lymphoid, and nonhematolymphoid markers. These findings were most consistent with PEL and erythroblastic sarcoma. RNA sequencing revealed the novel NFIA-RUNX1T1 fusion. Along with the previously reported PELs with NFIA-CBFA2T3 fusions, we describe a subset of PELs that occur in children, that frequently display extramedullary disease, and that harbor rearrangements of NFIA with core binding factor genes. We hypothesize that, together, these cases represent a rare but distinct clinicopathologic group of pediatric PELs with recurrent genetic abnormality.

King RL ，Siaghani PJ ，Wong K ，Edlefsen K ，Shane L ，Howard MT ，Reichard KK ，Mai M ，Viswanatha DS ，Greipp PT ，Goble TA ，Ruiz M ，Hara H ... -  《-》

CNS erythroblastic sarcoma: a potential emerging pediatric tumor type characterized by NFIA::RUNX1T1/3 fusions.

Tauziède-Espariat A ，Lew-Derivry L ，Abbou S ，Métais A ，Pierron G ，Reynaud S ，Masliah-Planchon J ，Mariet C ，Hasty L ，Dangouloff-Ros V ，Boddaert N ，Csanyi M ，Aline-Fardin A ，Lamaison C ，Chrétien F ，Beccaria K ，Puget S ，Varlet P ... -  《Acta Neuropathologica Communications》

Primary central nervous system erythroid sarcoma with NFIA-CBFA2T3 translocation: A rare but distinct clinicopathologic entity.

Linnik Y ，Pastakia D ，Dryden I ，Head DR ，Mason EF ... -  《-》

De novo primary central nervous system pure erythroid leukemia/sarcoma with t(1;16)(p31;q24) NFIA/CBFA2T3 translocation.

Liu H ，Guinipero TL ，Schieffer KM ，Carter C ，Colace S ，Leonard JR ，Orr BA ，Kahwash SB ，Brennan PJ ，Fitch JR ，Kelly B ，Magrini VJ ，White P ，Wilson RK ，Mardis ER ，Cottrell CE ，Boué DR ... -  《-》