Myoepithelial carcinoma of soft tissue is a rare, malignant neoplasm that is morphologically and immunophenotypically similar to its counterpart in salivary gland. It demonstrates myoepithelial differentiation, possessing both epithelial and myogenic characteristics. Thought to be chemotherapy insensitive, the optimal treatment regimen of this tumor has yet to be established and only a select few cases in the literature discuss treatment efficacy in detail.
Here we present a case of a young adult with metastatic myoepithelial carcinoma with an initial excellent response to systemic therapy utilizing carboplatin and paclitaxel with continued complete response after 3 years. The patient also underwent complete surgical excision and received adjuvant radiation to the primary site of disease. Exome sequencing revealed an inactivating mutation in RB1 which we believe to be the first such mutation to be reported in this cancer type.
Given increasing evidence suggesting RB1 loss is associated with responsiveness to conventional chemotherapies, particularly platinum-based regimens, we hypothesize that this genetic feature predisposed chemosensitivity in our patient’s tumor.
Gleason BC, Hornick JL. Myoepithelial tumours of skin and soft tissue: an update. Diagnostic Histopathology. 2008;14:552–62. CrossRef
Antonescu CR, Zhang L, Chang NE, Pawel BR, Travis W, Katabi N, Edelman M, Rosenberg AE, Nielsen GP, Dal Cin P, Fletcher CD. 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. 2010;49:1114–24. CrossRefPubMedPubMedCentral
Le Loarer F, Zhang L, Fletcher CD, Ribeiro A, Singer S, Italiano A, Neuville A, Houlier A, Chibon F, Coindre JM, Antonescu CR. 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. 2014;53:475–86. CrossRefPubMedPubMedCentral
DePristo MA, Banks E, Poplin R, Garimella KV, Maguire JR, Hartl C, Philippakis AA, del Angel G, Rivas MA, Hanna M, et al. A framework for variation discovery and genotyping using next-generation DNA sequencing data. Nat Genet. 2011;43:491–8. doi: 10.1038/ng.1806. Epub 2011 Apr 1010 CrossRefPubMedPubMedCentral
Cassier PA, Fumagalli E, Rutkowski P, Schoffski P, Van Glabbeke M, Debiec-Rychter M, Emile JF, Duffaud F, Martin-Broto J, Landi B, et al. Outcome of patients with platelet-derived growth factor receptor alpha-mutated gastrointestinal stromal tumors in the tyrosine kinase inhibitor era. Clin Cancer Res. 2012;18:4458–64. CrossRefPubMed
Rastrelli M, Passuello N, Cecchin D, Basso U, Tosi AL, Rossi CR. Metastatic malignant soft tissue myoepithelioma: a case report showing complete response after locoregional and systemic therapy. J Surg Case Rep. 2013;16(12). doi: 10.1093/jscr/rjt109.
Fletcher CDM, World Health Organization. International Agency for Research on Cancer.: WHO classification of tumours of soft tissue and bone. Lyon: IARC Press; 2013.
Rodriguez ML, Juarez CP, Luna JD. Intravitreal triamcinolone acetonide injection in blind painful eyes. Intraocular steroids as a treatment for blind painful red eyes. Eur J Ophthalmol. 2003;13:292–7. PubMed
- Myoepithelial carcinoma with RB1 mutation: remarkable chemosensitivity to carcinoma of unknown origin therapy
Timothy M. Hoggard
Marilyn M. Bui
Jamie K. Teer
Ricardo J. Gonzalez
Andrew S. Brohl
Damon R. Reed
- BioMed Central
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