https://doi.org/10.4081/jbr.2026.14434
Primary breast Ewing sarcoma in a young adult: diagnostic challenges and neoadjuvant chemotherapy success
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Published: 2 March 2026
Extra-skeletal Ewing Sarcoma (EES) is a malignant soft-tissue tumor morphologically indistinguishable from osseous Ewing Sarcoma (ES). The Ewing family includes ES, EES, Askin tumor, and peripheral primitive neuroectodermal tumor. About 85% harbor the t(11;22) (q24;q12) fusion by fluorescence in situ hybridization producing a chimeric protein central to pathogenesis. EES is rare, highly aggressive, and prone to recurrence, typically affecting adolescents and young adults and arising in the trunk or lower limbs; primary breast origin is exceptionally uncommon and carries a poor prognosis relative to other breast malignancies and versus other extra-skeletal ES sites. We report the case of a 37-year-old woman with a rapidly enlarging breast mass. Imaging suggested a cyst-like lesion; a core biopsy was non-diagnostic. Wide excision established ES. She received neoadjuvant chemotherapy with complete response, followed by mastectomy. This case and literature review underscore the rarity of primary breast ES and the value of neoadjuvant chemotherapy in management.
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1. Ewing J. Classics in oncology. Diffuse endothelioma of bone. James Ewing. Proceedings of the New York Pathological Society, 1921. CA Cancer J Clin 1972;22:95–8. DOI: https://doi.org/10.3322/canjclin.22.2.95
2. Mukhopadhyay P, Gairola M, Sharma M, et al. Primary spinal epidural extraosseous Ewing’s sarcoma: report of five cases and literature review. Australas Radiol 2001;45:372–9. DOI: https://doi.org/10.1046/j.1440-1673.2001.00942.x
3. Grossniklaus HE, Shehata B, Sorensen P, et al. Primitive neuroectodermal tumor/Ewing sarcoma of the retina. Arch Pathol Lab Med 2012;136:829–31. DOI: https://doi.org/10.5858/arpa.2011-0403-CR
4. Balamuth NJ, Womer RB. Ewing’s sarcoma. Lancet Oncol 2010;11:184–92. DOI: https://doi.org/10.1016/S1470-2045(09)70286-4
5. Setty BA, Gikandi A, DuBois SG. Ewing sarcoma drug therapy: current standard of care and emerging agents. Paediatr Drugs 2023;25:389–97. DOI: https://doi.org/10.1007/s40272-023-00568-9
6. Angervall L, Enzinger FM. Extraskeletal neoplasm resembling Ewing’s sarcoma. Cancer 1975;36:240–51. DOI: https://doi.org/10.1002/1097-0142(197507)36:1<240::AID-CNCR2820360127>3.0.CO;2-H
7. Basma E, Hajar H, Nabil M, et al. Breast Ewing sarcoma/primitive neuroectodermal tumor: a case report and a review of the literature. Breast 2012;3:5.
8. Kwak J-Y, Kim E-K, You JK, et al. Metastasis of primitive neuroectodermal tumor to the breast. J Clin Ultrasound JCU 2002;30:374–7. DOI: https://doi.org/10.1002/jcu.10076
9. Seong BKA, Dharia NV, Lin S, et al. TRIM8 modulates the EWS/FLI oncoprotein to promote survival in Ewing sarcoma. Cancer Cell 2021;39:1262-78.e7. DOI: https://doi.org/10.1016/j.ccell.2021.07.003
10. Theisen ER, Pishas KI, Saund RS, Lessnick SL. Therapeutic opportunities in Ewing sarcoma: EWS-FLI inhibition via LSD1 targeting. Oncotarget 2016;7:17616–30. DOI: https://doi.org/10.18632/oncotarget.7124
11. Tamura G, Sasou S, Kudoh S, et al. Primitive neuroectodermal tumor of the breast: immunohistochemistry and fluorescence in situ hybridization. Pathol Int 2007;57:509–12. DOI: https://doi.org/10.1111/j.1440-1827.2007.02132.x
12. Folpe AL, Goldblum JR, Rubin BP, et al. Morphologic and immunophenotypic diversity in Ewing family tumors: a study of 66 genetically confirmed cases. Am J Surg Pathol 2005;29:1025–33. DOI: https://doi.org/10.1097/01.pas.0000167056.13614.62
13. Verrill MW, Judson IR, Harmer CL, et al. Ewing’s sarcoma and primitive neuroectodermal tumor in adults: are they different from Ewing’s sarcoma and primitive neuroectodermal tumor in children? J Clin Oncol Off J Am Soc Clin Oncol 1997;15:2611–21. DOI: https://doi.org/10.1200/JCO.1997.15.7.2611
14. da Silva BB, Lopes-Costa PV, Pires CG, et al. Primitive neuroectodermal tumor of the breast. Eur J Obstet Gynecol Reprod Biol 2008;137:248–9. DOI: https://doi.org/10.1016/j.ejogrb.2006.11.013
15. Maxwell RW, Ghate SV, Bentley RC, Soo MS. Primary primitive neuroectodermal tumor of the breast. J Ultrasound Med 2006;25:1331–3. DOI: https://doi.org/10.7863/jum.2006.25.10.1331
16. Paulussen M, Ahrens S, Dunst J, et al. Localized Ewing tumor of bone: final results of the cooperative Ewing’s sarcoma study CESS 86. J Clin Oncol Off J Am Soc Clin Oncol 2001;19:1818–29. DOI: https://doi.org/10.1200/JCO.2001.19.6.1818
17. Ko K, Kim EA, Lee ES, Kwon Y. Primary primitive neuroectodermal tumor of the breast: a case report. Korean J Radiol 2009;10:407–10. DOI: https://doi.org/10.3348/kjr.2009.10.4.407
18. Vindal A, Kakar AK. Primary primitive neuroectodermal tumor of the breast. J Clin Oncol Off J Am Soc Clin Oncol 2010;28:e453-455. DOI: https://doi.org/10.1200/JCO.2009.26.7542
19. Chuthapisith S, Prasert W, Warnnissorn M, et al. Ewing’s sarcoma and primitive neuroectodermal tumour (ES/PNET) presenting as a breast mass. Oncol Lett 2012;4:67–70. DOI: https://doi.org/10.3892/ol.2012.698
20. Majid N, Amrani M, Ghissassi I, et al. Bilateral Ewing sarcoma/primitive neuroectodermal tumor of the breast: a very rare entity and review of the literature. Case Rep Oncol Med 2013;2013:964568. DOI: https://doi.org/10.1155/2013/964568
21. Mahajan M, Raju KVVN, Rehmani K, et al. Primitive neuroectodermal tumour of breast—A case report. Indian J Surg Oncol 2014;5:89–91. DOI: https://doi.org/10.1007/s13193-014-0289-4
22. Ranade M, Shah A, Desai SB, Rekhi B. A curious case of Ewing sarcoma with epithelial differentiation, presenting as a breast mass. Breast J 2020;26:2244–5. DOI: https://doi.org/10.1111/tbj.14045
23. Meddeb S, Rhim MS, Kouira M, et al. Ewing’s sarcoma: an uncommon breast tumor. Clin Pract 2014;4:659. DOI: https://doi.org/10.4081/cp.2014.659
24. Kim YS, Lee KH, Choi SJ, et al. Extraskeletal Ewing’s sarcoma of the breast, mimicking cyst. J Korean Surg Soc 2016;79:411–4. DOI: https://doi.org/10.4174/jkss.2010.79.5.411
25. Popli MB, Popli V, Bahl P, Solanki Y. Extraskeletal Ewing’s sarcoma of the breast. Eur J Radiol Extra 2009;70:e65–7. DOI: https://doi.org/10.1016/j.ejrex.2008.11.005
26. Srivastava S, Arora J, Parakh A, Goel RK. Primary extraskeletal Ewing’s sarcoma/primitive neuroectodermal tumor of breast. Indian J Radiol Imaging 2016;26:226–30. DOI: https://doi.org/10.4103/0971-3026.184408
27. Ikhwan SM, Kenneth VKT, Seoparjoo A, Zin AAM. Primary extraskeletal Ewing’s sarcoma/primitive neuroectodermal tumour of breast. BMJ Case Rep 2013;2013:bcr2013009584. DOI: https://doi.org/10.1136/bcr-2013-009584
28. Thakur R, Venugopal R, Sharma J, Barwad A. A rare occurrence of Ewing’s sarcoma presenting as breast mass: a case report and literature review. Cancer Plus 2022;4:1–5. DOI: https://doi.org/10.18063/cp.v4i3.385
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