Encyclopedia of Pathology

Living Edition
| Editors: J.H.J.M. van Krieken

Mixed Tumor, Myoepithelioma of Soft Tissue

  • Alessandro FranchiEmail author
Living reference work entry
DOI: https://doi.org/10.1007/978-3-319-28845-1_5426-1



Myoepithelioma is defined as a tumor composed entirely of neoplastic cells with myoepithelial differentiation. The term mixed tumor is used when tubular and/or ductal differentiation is present. However, it is now widely accepted that myoepithelioma and mixed tumor of the soft tissues represent a spectrum of closely related tumors with overlapping histologic features and similar clinical behavior. Malignant myoepithelioma or myoepithelial carcinoma represents the malignant counterpart.

Clinical Features

  • Incidence

    Soft tissue myoepithelial tumors are uncommon.

  • Age

    They occur over a wide age range, having been reported in infants and adults. The peak age is between the third and fifth decades (Kilpatrick et al. 1997; Michal and Miettinen 1999; Hornick and Fletcher 2003; Gleason and Fletcher 2007; Rekhi et al. 2012; Thway and Fisher 2014; Jo and Fletcher 2015).

  • Sex

    There is no significant gender predilection (Hornick and Fletcher 2003; Thway and Fisher 2014)....

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References and Further Reading

  1. Agaram, N. P., Chen, H. W., Zhang, L., et al. (2015). EWSR1-PBX3: A novel gene fusion in myoepithelial tumors. Genes, Chromosomes & Cancer, 54, 63–71.CrossRefGoogle Scholar
  2. Antonescu, C. R., Zhang, L., Chang, N. E., et al. (2010). EWSR1-POU5F1 fusion in soft tissue myoepithelial tumors. A molecular analysis of sixty-six cases, including soft tissue, bone, and visceral lesions, showing common involvement of the EWSR1 gene. Genes, Chromosomes & Cancer, 49, 1114–1124.CrossRefGoogle Scholar
  3. Antonescu, C. R., Katabi, N., Zhang, L., et al. (2011). EWSR1-ATF1 fusion is a novel and consistent finding in hyalinizing clear-cell carcinoma of salivary gland. Genes, Chromosomes & Cancer, 50, 559–570.CrossRefGoogle Scholar
  4. Antonescu, C. R., Zhang, L., Shao, S. Y., Mosquera, J. M., Weinreb, I., Katabi, N., & Fletcher, C. D. (2013). Frequent PLAG1 gene rearrangements in skin and soft tissue myoepithelioma with ductal differentiation. Genes, Chromosomes & Cancer, 52, 675–682.CrossRefGoogle Scholar
  5. Brandal, P., Panagopoulos, I., Bjerkehagen, B., et al. (2008). Detection of a t(1,22)(q23;q12) translocation leading to an EWSR1-PBX1 fusion gene in a myoepithelioma. Genes, Chromosomes & Cancer, 47, 558–564.CrossRefGoogle Scholar
  6. Brandal, P., Panagopoulos, I., Bjerkehagen, B., et al. (2009). t(19,22)(q13;q12) translocation leading to the novel fusion gene EWSR1-ZNF444 in soft tissue myoepithelial carcinoma. Genes, Chromosomes & Cancer, 48, 1051–1056.CrossRefGoogle Scholar
  7. Domingo-Musibay, E., Oliveira, A. M., Okuno, S. H., Petersen, I. A., Rose, P. S., & Robinson, S. I. (2018). Myoepithelioma of soft tissues: A single institution retrospective case series. American Journal of Clinical Oncology, 41, 357–361.PubMedGoogle Scholar
  8. Flucke, U., Tops, B. B., Verdijk, M. A., van Cleef, P. J., van Zwam, P. H., Slootweg, P. J., Bovée, J. V., Riedl, R. G., Creytens, D. H., Suurmeijer, A. J., & Mentzel, T. (2012). NR4A3 rearrangement reliably distinguishes between the clinicopathologically overlapping entities myoepithelial carcinoma of soft tissue and cellular extraskeletal myxoid chondrosarcoma. Virchows Archiv, 460, 621–628.CrossRefGoogle Scholar
  9. Gebre-Medhin, S., Nord, K. H., Moller, E., et al. (2012). Recurrent rearrangement of the PHF1 gene in ossifying fibromyxoid tumors. The American Journal of Pathology, 181, 1069–1077.CrossRefGoogle Scholar
  10. Gleason, B. C., & Fletcher, C. D. (2007). Myoepithelial carcinoma of soft tissue in children: An aggressive neoplasm analyzed in a series of 29 cases. The American Journal of Surgical Pathology, 31, 1813–1824.CrossRefGoogle Scholar
  11. Hornick, J. L., & Fletcher, C. D. (2003). Myoepithelial tumors of soft tissue: A clinicopathologic and immunohistochemical study of 101 cases with evaluation of prognostic parameters. The American Journal of Surgical Pathology, 27, 1183–1196.CrossRefGoogle Scholar
  12. Hornick, J. L., Dal Cin, P., & Fletcher, C. D. (2009). Loss of INI1 expression is characteristic of both conventional and proximal-type epithelioid sarcoma. The American Journal of Surgical Pathology, 33, 542–550.CrossRefGoogle Scholar
  13. Jo, V. Y., & Fletcher, C. D. (2011). p63 immunohistochemical staining is limited in soft tissue tumors. American Journal of Clinical Pathology, 136(5), 762–766.CrossRefGoogle Scholar
  14. Jo, V. Y., & Fletcher, C. D. (2015). Myoepithelial neoplasms of soft tissue: An updated review of the clinicopathologic, immunophenotypic, and genetic features. Head and Neck Pathology, 9, 32–38.CrossRefGoogle Scholar
  15. Kilpatrick, S. E., Hitchcock, M. G., Kraus, M. D., Calonje, E., & Fletcher, C. D. (1997). Mixed tumors and myoepitheliomas of soft tissue: A clinicopathologic study of 19 cases with a unifying concept. The American Journal of Surgical Pathology, 21, 13–22.CrossRefGoogle Scholar
  16. Le Loarer, F., Zhang, L., Fletcher, C. D., et al. (2014). Consistent SMARCB1 homozygous deletions in epithelioid sarcoma and in a subset of myoepithelial carcinomas can be reliably detected by FISH in archival material. Genes, Chromosomes & Cancer, 53, 475–486.CrossRefGoogle Scholar
  17. Michal, M., & Miettinen, M. (1999). Myoepitheliomas of the skin and soft tissues. Report of 12 cases. Virchows Archiv, 434, 393–400.CrossRefGoogle Scholar
  18. Rekhi, B., Sable, M., & Jambhekar, N. A. (2012). Histopathological, immunohistochemical and molecular spectrum of myoepithelial tumours of soft tissues. Virchows Archiv, 461, 687–697.CrossRefGoogle Scholar
  19. Thway, K., & Fisher, C. (2014). Myoepithelial tumor of soft tissue: Histology and genetics of an evolving entity. Advances in Anatomic Pathology, 21, 411–419.CrossRefGoogle Scholar

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Authors and Affiliations

  1. 1.Department of Translational Research and of New Technologies in Medicine and SurgeryUniversity of Pisa, ItalyPisaItaly