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Identification of EWSR1 rearrangements in patients with immature hematopoietic neoplasms: A case series and review of literature. Ann Diagn Pathol 2022; 58:151942. [PMID: 35344861 DOI: 10.1016/j.anndiagpath.2022.151942] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2022] [Accepted: 03/17/2022] [Indexed: 11/20/2022]
Abstract
Rearrangement of the EWSR1 gene (22q12.2) is a well-recognized genetic lesion in bone and soft tissue tumors. However, few reports have suggested that EWSR1 rearrangements may also occur in the setting of hematopoietic tumors. We herein describe two cases of immature hematopoietic neoplasms presenting with EWSR1 rearrangements. The first occurred in a 41-year-old female diagnosed with mixed-phenotype acute leukemia, B/T/myeloid, in which conventional chromosome analysis revealed a t(2;22)(q35;q12). Further analysis with whole genome sequencing revealed that this rearrangement led to an EWSR1::FEV gene fusion. The second case was identified in an 18-year-old male with a high-grade B-cell lineage malignant neoplasm with immature features in which conventional chromosome analysis revealed a t(17;22)(q25;q12). Mate-pair sequencing, a next generation sequencing-based assay, was performed and revealed three in-frame chimeric gene fusions involving the EWSR1, TEF and STRADA gene regions. This report further expands the repertoire of hematopoietic neoplasms with EWSR1 fusions and partner genes involved in these rearrangements.
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Mixed Phenotype Acute Leukemia, B/Myeloid (Bilineal and Biphenotypic), With t(2;22)(q35;q12);EWSR1-FEV. J Pediatr Hematol Oncol 2021; 43:e388-e394. [PMID: 32925408 DOI: 10.1097/mph.0000000000001934] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/24/2019] [Accepted: 08/05/2020] [Indexed: 11/26/2022]
Abstract
BACKGROUND Ewing sarcoma breakpoint region 1 gene (EWSR1) rearrangements are largely associated with the Ewing sarcoma family of tumors. OBSERVATIONS We report the first case of infantile, mixed phenotype acute leukemia, B/myeloid (bilineal and biphenotypic [B-lymphoid and B-lymphoid/myeloid]), with a t(2;22)(q35;q12). The EWSR1-fifth Ewing variant gene fusion and nonsense mutation in STAG2 were detected by next-generation sequencing and markedly high expression of fifth Ewing sarcoma variant mRNA detected by quantitative reverse transcription polymerase chain reaction. The patient was treated with a combined myeloid/lymphoid leukemia regimen followed by allogeneic stem cell transplant and was in complete remission at 3.8-year follow-up. CONCLUSIONS Our case study underscores the importance of a comprehensive evaluation of acute leukemia and provides insights into the phenotype of EWSR1 rearranged neoplasms in the context of partner genes and cell type.
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Endo A, Tomizawa D, Aoki Y, Morio T, Mizutani S, Takagi M. EWSR1/ELF5 induces acute myeloid leukemia by inhibiting p53/p21 pathway. Cancer Sci 2016; 107:1745-1754. [PMID: 27627705 PMCID: PMC5198945 DOI: 10.1111/cas.13080] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2016] [Revised: 08/26/2016] [Accepted: 09/09/2016] [Indexed: 02/06/2023] Open
Abstract
The Ewing sarcoma breakpoint region 1 (EWSR1) gene is known to fuse with various partner genes to promote the development of the Ewing sarcoma family of tumors and other sarcomas. In contrast, the association of EWSR1 chimeric fusion genes with leukemia has rarely been reported. We identified a novel EWSR1‐associated chimeric fusion gene in a patient with acute myeloid leukemia harboring 46, XY, t (11; 22) (p13; q12) karyotype abnormality. The patient was refractory to intensified chemotherapy including hematopoietic stem cell transplantation. Total RNA paired‐end sequencing identified a novel chimeric fusion gene as EWSR1/ELF5, a member of the E26 transformation‐specific transcription factor family. Transduction of EWSR1/ELF5 to NIH3T3 cells induced transformation by attenuating with the p53/p21‐dependent pathway. The injection of EWSR1/ELF5‐transduced NIH3T3 cells into NSG‐SCID mice systematically induced the development of tumors in vivo. These results revealed the oncogenic potency of EWSR1/ELF5.
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Affiliation(s)
- Akifumi Endo
- Department of Pediatrics and Developmental Biology, Tokyo Medical and Dental University, Tokyo, Japan
| | - Daisuke Tomizawa
- Department of Pediatrics and Developmental Biology, Tokyo Medical and Dental University, Tokyo, Japan.,Division of Leukemia and Lymphoma, Children's Cancer Center, National Center for Child Health and Development, Tokyo, Japan
| | - Yuki Aoki
- Department of Pediatrics and Developmental Biology, Tokyo Medical and Dental University, Tokyo, Japan.,Department of Pediatric Oncology, National Cancer Center, Tokyo, Japan
| | - Tomohiro Morio
- Department of Pediatrics and Developmental Biology, Tokyo Medical and Dental University, Tokyo, Japan
| | - Shuki Mizutani
- Department of Pediatrics and Developmental Biology, Tokyo Medical and Dental University, Tokyo, Japan
| | - Masatoshi Takagi
- Department of Pediatrics and Developmental Biology, Tokyo Medical and Dental University, Tokyo, Japan
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Pierini T, Di Giacomo D, Pierini V, Gorello P, Barba G, Lema Fernandez AG, Pellanera F, Iannotti T, Falzetti F, La Starza R, Mecucci C. MYB deregulation from a EWSR1-MYB fusion at leukemic evolution of a JAK2 (V617F) positive primary myelofibrosis. Mol Cytogenet 2016; 9:68. [PMID: 27594918 PMCID: PMC5009546 DOI: 10.1186/s13039-016-0277-1] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2016] [Accepted: 08/22/2016] [Indexed: 02/08/2023] Open
Abstract
Background Although Philadelphia-negative myeloproliferative neoplasms (Ph-MPN) are usually not aggressive, the type and the number of molecular lesions impact greatly on leukemic transformation. Indeed, the molecular background underlying progression is still largely unexplored even though ASXL1, IDH1/2, SRSF2, and TP53 mutations, together with adverse karyotypic changes, place the patient at high risk of leukemic transformation. Case presentation Our patient, a 64-year old man with a diagnosis of JAK2V617F primary myelofibrosis (PMF) had an unusually rapid leukemic transformation. Genomic profiling showed that TET2 and SRSF2 mutations were also present. At leukemic transformation, the patient developed a complex chromosome rearrangement producing a EWSR1-MYB fusion. Remarkably, the expression of MYB and of its target BCL2 was, respectively, ≥4.7 and ≥2.8 fold higher at leukemic transformation than after chemotherapy, when the patient obtained the hematological remission. At this time point, the EWSR1-MYB fusion disappeared while JAK2V617F, TET2, and SRSF2 mutations, as well as PMF morphological features persisted. Conclusions Rapid leukemic transformation of JAK2V617F PMF was closely linked to a previously undescribed putative EWSR1-MYB transcription factor which was detected only at disease evolution. We hypothesize that the EWSR1-MYB contributed to leukemia transformation through at least two mechanisms: 1) it sustained MYB expression, and consequently deregulated its target BCL2, a putative onco-suppressor gene; and 2) ectopic EWSR1-MYB expression probably fulfilled its own oncogenic potential as demonstrated for other MYB-fusions. As our study confirmed that MYB is recurrently involved in chronic as well as leukemic transformation of PMF, it appears to be a valid molecular marker for tailored treatments. Electronic supplementary material The online version of this article (doi:10.1186/s13039-016-0277-1) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Tiziana Pierini
- Hematology and Bone Marrow Transplantation Unit, University of Perugia, C.R.E.O., Piazzale Menghini n.9, 06132 Perugia, Italy
| | - Danika Di Giacomo
- Hematology and Bone Marrow Transplantation Unit, University of Perugia, C.R.E.O., Piazzale Menghini n.9, 06132 Perugia, Italy
| | - Valentina Pierini
- Hematology and Bone Marrow Transplantation Unit, University of Perugia, C.R.E.O., Piazzale Menghini n.9, 06132 Perugia, Italy
| | - Paolo Gorello
- Hematology and Bone Marrow Transplantation Unit, University of Perugia, C.R.E.O., Piazzale Menghini n.9, 06132 Perugia, Italy
| | - Gianluca Barba
- Hematology and Bone Marrow Transplantation Unit, University of Perugia, C.R.E.O., Piazzale Menghini n.9, 06132 Perugia, Italy
| | - Anair Graciela Lema Fernandez
- Hematology and Bone Marrow Transplantation Unit, University of Perugia, C.R.E.O., Piazzale Menghini n.9, 06132 Perugia, Italy
| | - Fabrizia Pellanera
- Hematology and Bone Marrow Transplantation Unit, University of Perugia, C.R.E.O., Piazzale Menghini n.9, 06132 Perugia, Italy
| | - Tamara Iannotti
- Hematology and Bone Marrow Transplantation Unit, University of Perugia, C.R.E.O., Piazzale Menghini n.9, 06132 Perugia, Italy
| | - Franca Falzetti
- Hematology and Bone Marrow Transplantation Unit, University of Perugia, C.R.E.O., Piazzale Menghini n.9, 06132 Perugia, Italy
| | - Roberta La Starza
- Hematology and Bone Marrow Transplantation Unit, University of Perugia, C.R.E.O., Piazzale Menghini n.9, 06132 Perugia, Italy
| | - Cristina Mecucci
- Hematology and Bone Marrow Transplantation Unit, University of Perugia, C.R.E.O., Piazzale Menghini n.9, 06132 Perugia, Italy
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Sankar S, Lessnick SL. Promiscuous partnerships in Ewing's sarcoma. Cancer Genet 2011; 204:351-65. [PMID: 21872822 PMCID: PMC3164520 DOI: 10.1016/j.cancergen.2011.07.008] [Citation(s) in RCA: 164] [Impact Index Per Article: 12.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2011] [Revised: 07/18/2011] [Accepted: 07/19/2011] [Indexed: 12/16/2022]
Abstract
Ewing's sarcoma is a highly aggressive bone and soft tissue tumor of children and young adults. At the molecular genetic level Ewing's sarcoma is characterized by a balanced reciprocal translocation, t(11;22)(q24;q12), which encodes an oncogenic fusion protein and transcription factor EWS/FLI. This tumor-specific chimeric fusion retains the amino terminus of EWS, a member of the TET (TLS/EWS/TAF15) family of RNA-binding proteins, and the carboxy terminus of FLI, a member of the ETS family of transcription factors. In addition to EWS/FLI, variant translocation fusions belonging to the TET/ETS family have been identified in Ewing's sarcoma. These studies solidified the importance of TET/ETS fusions in the pathogenesis of Ewing's sarcoma and have since been used as diagnostic markers for the disease. EWS fusions with non-ETS transcription factor family members have been described in sarcomas that are clearly distinct from Ewing's sarcoma. However, in recent years there have been reports of rare fusions in "Ewing's-like tumors" that harbor the amino-terminus of EWS fused to the carboxy-terminal DNA or chromatin-interacting domains contributed by non-ETS proteins. This review aims to summarize the growing list of fusion oncogenes that characterize Ewing's sarcoma and Ewing's-like tumors and highlights important questions that need to be answered to further support the existing concept that Ewing's sarcoma is strictly a "TET/ETS" fusion-driven malignancy. Understanding the molecular mechanisms of action of the various different fusion oncogenes will provide better insights into the biology underlying this rare but important solid tumor.
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Affiliation(s)
- Savita Sankar
- Department of Oncological Sciences, University of Utah School of Medicine, Salt Lake City, UT, USA 84112
| | - Stephen L. Lessnick
- Department of Oncological Sciences, University of Utah School of Medicine, Salt Lake City, UT, USA 84112
- Center for Children’s Cancer Research at Huntsman Cancer Institute, University of Utah, Salt Lake City, UT, USA 84112
- Division of Pediatric Hematology/Oncology, University of Utah School of Medicine, Salt Lake City, UT
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Mesenchymal Stem Cells and the Origin of Ewing's Sarcoma. Sarcoma 2010; 2011. [PMID: 20953407 PMCID: PMC2952797 DOI: 10.1155/2011/276463] [Citation(s) in RCA: 60] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2010] [Accepted: 09/06/2010] [Indexed: 12/17/2022] Open
Abstract
The origin of Ewing's sarcoma is a subject of much debate. Once thought to be derived from primitive neuroectodermal cells, many now believe it to arise from a mesenchymal stem cell (MSC). Expression of the EWS-FLI1 fusion gene in MSCs changes cell morphology to resemble Ewing's sarcoma and induces expression of neuroectodermal markers. In murine cells, transformation to sarcomas can occur. In knockdown experiments, Ewing's sarcoma cells develop characteristics of MSCs and the ability to differentiate into mesodermal lineages. However, it cannot be concluded that MSCs are the cell of origin. The concept of an MSC still needs to be rigorously defined, and there may be different subpopulations of mesenchymal pluripotential cells. Furthermore, EWS-FLI1 by itself does not transform human cells, and cooperating mutations appear to be necessary. Therefore, while it is possible that Ewing's sarcoma may originate from a primitive mesenchymal cell, the idea needs to be refined further.
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Jakovljević G, Nakić M, Rogosić S, Kardum-Skelin I, Mrsić-Davidović S, Zadro R, Kruslin B. Pre-B-cell acute lymphoblastic leukemia with bulk extramedullary disease and chromosome 22 (EWSR1) rearrangement masquerading as Ewing sarcoma. Pediatr Blood Cancer 2010; 54:606-9. [PMID: 20049929 DOI: 10.1002/pbc.22365] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
We report a 2-year-old female with a subcutaneous tumor who was initially misdiagnosed as suffering from Ewing sarcoma with a positive EWSR1 rearrangement and EWS/FLI1 transcript. After finding lymphoblasts in peripheral blood, the diagnosis of acute lymphoblastic leukemia was established. This necessitated further analysis of the subcutaneous tumor. The tissue was positive for immature B-cell markers and an immunoglobulin heavy chain gene rearrangement, which confirmed the final diagnosis of common type acute lymphoblastic leukemia with bulk extramedullary disease. The patient was treated with chemotherapy and was in remission 30 months after the diagnosis.
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Affiliation(s)
- Gordana Jakovljević
- Department of Hematology and Oncology, Pediatric Clinic, Children's Hospital Zagreb, Zagreb, Croatia.
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Butros LJ, Phillip S, Chou A, Meyers PA, Huvos AG, Healey JH, Russo P, Gorlick RG. Leydig cell tumor after treatment for Ewing's sarcoma. Pediatr Blood Cancer 2007; 49:1008-10. [PMID: 16526050 DOI: 10.1002/pbc.20825] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
Leydig cell tumors account for 3% of testicular tumors and have never been reported after treatment for Ewing's sarcoma. We report the unusual occurrence of a patient who developed a Leydig cell tumor of the testis 18 years after successful treatment for Ewing's sarcoma. Additional monitoring for second malignancies may become appropriate as long-term survival continues to improve for patients with Ewing's sarcoma.
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Affiliation(s)
- Linda J Butros
- Department of Pediatrics, University of New Mexico Health Sciences Center, Albuquerque, New Mexico, USA
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9
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Ozdemirli M, Fanburg-Smith JC, Hartmann DP, Azumi N, Miettinen M. Differentiating lymphoblastic lymphoma and Ewing's sarcoma: lymphocyte markers and gene rearrangement. Mod Pathol 2001; 14:1175-82. [PMID: 11706081 DOI: 10.1038/modpathol.3880455] [Citation(s) in RCA: 53] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
We encountered a child with an intraosseous small round cell tumor that was negative for LCA, CD20 (L26), and CD3 and positive for vimentin, CD99 (MIC-2), and periodic acid-Schiff. The tumor exhibited rosette-like formations. This case was initially interpreted as Ewing's sarcoma (ES); however, additional studies revealed positivity for CD79a, CD43, and TdT expression, and an immunoglobulin heavy chain gene rearrangement (IgH-R) by polymerase chain reaction (PCR) established this to be a precursor B-lymphoblastic lymphoma. Because the differential diagnosis of ES and lymphoblastic lymphoma can be difficult and the differential diagnostic value of leukocyte antigens and immunoglobulin heavy chain gene rearrangement studies have not been fully evaluated, we conducted a more extensive investigation on 33 (21 soft tissue and 12 intraosseous) ES cases. Cases were retrieved from the files of the Department of Pathology at Georgetown University and from the Soft Tissue Registry of the Armed Forces Institute of Pathology. The cases were studied by light microscopy, immunohistochemistry, and PCR for IgH-R and T cell receptor gamma chain gene rearrangement (Tgamma-R). There were 17 females and 16 males; the mean age was 29.3 years. Locations included the extremities (n = 17) and trunk (n = 16). All cases fit the ES spectrum by light microscopy and immunohistochemistry, as previously determined, and were negative for lymphoid markers (LCA, CD3, CD20, CD43, CD79a, and TdT), CD10 and CD34. CD99 was positive in 31/33 and bcl-2 was weakly positive in 13/33 cases. All 21 cases studied for gene rearrangements by PCR were negative for IgH-R and Tgamma-R. Distinction of intraosseous lymphoblastic lymphoma from ES may be difficult because lymphomas may occasionally exhibit unexpected morphologic and immunophenotypic properties including LCA, CD3 and CD20 negativity and cytokeratin positivity. Additional analysis using CD79a, CD43, TdT, and PCR should be performed to avoid misdiagnosis. True ES is negative for lymphoid markers including CD79a, CD43, and TdT, as well as for IgH-R and Tgamma-R.
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Affiliation(s)
- M Ozdemirli
- Department of Pathology, Georgetown University Medical Center, 3900 Reservoir Road N.W., Washington, DC 20007, USA
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Rosoff PM, Hatcher S, West DC. Biphenotypic sarcoma with characteristics of both a Ewing sarcoma and a desmoplastic small round cell tumor. MEDICAL AND PEDIATRIC ONCOLOGY 2000; 34:407-12. [PMID: 10842247 DOI: 10.1002/(sici)1096-911x(200006)34:6<407::aid-mpo5>3.0.co;2-x] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
BACKGROUND The EWS gene, a transcription factor of unknown function, is involved in chromosomal translocations associated with a wide variety of tumors, particularly small round blue cell tumors such as Ewing sarcoma. It has previously been reported that desmoplastic small round blue cell tumor (DSRBCT) frequently has an associated t(11;22) abnormality resulting from fusion of the EWS and WT-1 genes. PROCEDURE We report a case of a small round blue cell tumor with characteristics of both Ewing sarcoma and DSRBCT with a t(11;22) translocation leading to fusion of the EWS and FLI1genes. RESULTS The translocation point and fusion products were confirmed by polymerase chain reaction amplification and restriction fragment mapping of the products. CONCLUSIONS The biphenotypic nature of this case and the apparent promiscuity of the EWS gene in tumor-associated translocations coupled with other reports of biphenotypic childhood sarcomas has potential implications for the relationship between small round blue cell tumors and the mechanism of EWS/FLI1 oncogenesis.
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MESH Headings
- Carcinoma, Small Cell/diagnostic imaging
- Carcinoma, Small Cell/genetics
- Carcinoma, Small Cell/pathology
- Chromosome Mapping
- Chromosomes, Human, Pair 11/genetics
- Chromosomes, Human, Pair 22/genetics
- Electrophoresis, Agar Gel
- Fibromatosis, Aggressive/genetics
- Fibromatosis, Aggressive/pathology
- Humans
- Phenotype
- Photomicrography
- Reverse Transcriptase Polymerase Chain Reaction
- Sarcoma/diagnostic imaging
- Sarcoma/genetics
- Sarcoma/pathology
- Sarcoma, Ewing/diagnostic imaging
- Sarcoma, Ewing/genetics
- Sarcoma, Ewing/pathology
- Tomography, X-Ray Computed
- Translocation, Genetic
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Affiliation(s)
- P M Rosoff
- Division of Hematology-Oncology, Department of Pediatrics, Duke University Medical Center, Durham, North Carolina 27710, USA.
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Ozdemirli M, Fanburg-Smith JC, Hartmann DP, Shad AT, Lage JM, Magrath IT, Azumi N, Harris NL, Cossman J, Jaffe ES. Precursor B-Lymphoblastic lymphoma presenting as a solitary bone tumor and mimicking Ewing's sarcoma: a report of four cases and review of the literature. Am J Surg Pathol 1998; 22:795-804. [PMID: 9669342 DOI: 10.1097/00000478-199807000-00002] [Citation(s) in RCA: 77] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
Precursor B-lymphoblastic lymphoma (B-LBL) may present as a solitary bone tumor. Fewer than 10 cases with a proven precursor B-cell phenotype have been reported in the English literature. In this report, we describe four cases of B-lymphoblastic lymphoma presenting as a localized intraosseous mass, which clinically and histologically mimicked Ewing's sarcoma. Three tumors occurred in the tibia and one in the humerus. In all four cases, the initial diagnosis was either "Ewing's sarcoma" or "consistent with Ewing's sarcoma." All four patients were female. Three were children and one was an adult; mean age was 12.5 years (range, 4 to 31 years). All had extremity pain without significant constitutional symptoms. In three cases, the tumors were osteolytic on radiographic evaluation, and in one case, osteosclerotic. Immunohistochemical stains on paraffin-embedded tissue showed that the neoplastic cells expressed terminal deoxynucleotidyl transferase, CD43, vimentin, and CD99 (MIC2 gene product) in all cases. Three cases were negative for CD45. CD79a was positive in all four cases studied; however, CD20 (L26) was positive in only two of four cases. CD3 was negative in all cases. Two cases showed focal granular cytoplasmic staining for keratin. Two cases analyzed by polymerase chain reaction (PCR) revealed clonal rearrangement of the immunoglobulin heavy chain (IgH) gene. Follow-up revealed that the three pediatric patients, who received a high-dose multiagent chemotherapy regime for LBL, are disease free at follow-up intervals of more than 1, 11, and 12 years, respectively. The adult patient died two years after diagnosis with disseminated disease. Although rare, B-lymphoblastic lymphoma should be considered in the differential diagnosis of small round cell tumors of bone. A diagnosis of Ewing's sarcoma should be made only after complete immunophenotyping and, if necessary, molecular diagnostic tests to exclude lymphoblastic lymphoma. A limited panel of antibodies can lead to an erroneous diagnosis; B-lymphoblastic lymphoma may be negative for CD45 and CD20 but positive for CD99 and even for keratin, mimicking Ewing's sarcoma. Correct diagnosis is extremely important because LBL usually is curable in the pediatric age group with appropriate therapy.
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Affiliation(s)
- M Ozdemirli
- Department of Pathology, Georgetown University Medical Center, Washington, DC 20007, USA
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