Epithelial-Myoepithelial Carcinoma With High Grade Transformation
ABSTRACT Epithelial-myoepithelial carcinoma (EMC) is a rare salivary gland tumor of presumed intercalated duct origin with a low risk of metastasis and mortality. Factors shown to affect behavior include positive margins, vascular invasion, necrosis, and myoepithelial anaplasia. The latter category and dedifferentiated EMCs have been separated on the basis of presumed myoepithelial versus ductal origin, respectively. Three additional cases of typical EMC with transition to high-grade carcinoma are presented. Two of the tumors were stained with CAM5.2, 34betaE12, cytokeratin 14, p63, S100, calponin, smooth muscle actin, and muscle-specific actin. All tumors showed a gradual transition to a high-grade carcinoma from an EMC, each composed of clear cells even in the high-grade regions. One case also showed a discrete area with ductal lumina and another had plasmacytoid morphology. Squamous differentiation was seen in all cases as well. A consistent immunostaining pattern was not noted. Areas with focal lumina were diffusely positive for CAM5.2 only. Areas with clear cells showed patchy S100 positivity only, whereas cytokeratin 14 and 34betaE12-stained squamous pearls. The case with plasmacytoid morphology was diffusely positive for p63. No immunoexpression was noted with smooth muscle actin, muscle-specific actin, or calponin. It was not possible to convincingly separate the high-grade component in these cases into ductal dedifferentiated EMC versus myoepithelial. Recently, there has been a move to abandon the term "dedifferentiation" in favor of "high-grade transformation" in other salivary gland malignancies. We report these 3 such cases, review the literature and propose that these lesions be regarded as "EMC with high-grade transformation."
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ABSTRACT: Epithelial-myoepithelial carcinoma was first described by Danath et al. in 1972 and is classified as a rare low-grade biphasic neoplasm of the salivary glands. This case report presents a male patient who had a lesion in the oral mucosa with a history of recurrence of the tumor. The outcome resulted in a profile consistent with an epithelial-myoepithelial carcinoma with a high degree of transformation. The case highlights the importance of histopathological evaluation of oral lesions, which occasionally may not present typical clinical aspects of malignant lesion.The Open Dentistry Journal 07/2012; 6:111-7. DOI:10.2174/1874210601206010111
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ABSTRACT: The concept of dedifferentiation had previously been used in salivary gland carcinomas. Recently, the term "high-grade transformation" was introduced for adenoid cystic carcinoma, acinic cell carcinoma, epithelial-myoepithelial carcinoma, and polymorphous low-grade adenocarcinoma and may better reflect this phenomenon, although transformation into moderately differentiated adenocarcinoma (i.e., not "high grade") has also been described. Among the immunohistochemical markers, Ki-67 seems to be the only one that can help distinguish between the conventional and transformed components; however, the combination of morphological criteria is still sovereign. The overexpression of p53 was observed in the transformed component in all tumor types studied, despite few cases having been demonstrated to carry mutations or deletions in TP53 gene. Genetic studies in salivary gland tumors with dedifferentiation/high-grade transformation are rare and deserve further investigation. This paper aims at providing an overview on the recent concepts in histopathological classification of salivary gland tumors, complemented by immunohistochemical and genetic findings.08/2011; 2011:325965. DOI:10.4061/2011/325965
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ABSTRACT: Epithelial-myoepithelial carcinoma (EMC) is a rare low-grade salivary gland malignancy of presumed intercalated duct origin comprising 1% of all salivary gland tumours. High grade transformation (HGT) in EMC is a recently recognised entity with only a few cases reported in the literature. The authors report an additional case of EMC with HGT involving the submandibular gland. The patient was a 60-year-old woman who requested examination of the rapid growth of a mass in the left submandibular area, which she had first noticed 20 years previously. Histologically, the tumour had two distinct carcinomatous components. One component had features of a low grade EMC. The second component consisted of polygonal cells, arranged in a solid and nested pattern, with marked nuclear pleomorphism, brisk mitotic activity, and frequent necrosis. The Ki-67 labelling index of the EMC component was 9%, and that of the high grade component was 40%. The patient developed multiple pulmonary metastases 15 months after surgery. The aggressive behaviour of EMC with HGT suggests that it is important to recognise this variant of EMC to avoid misdiagnosis and inappropriate treatment.International Journal of Oral and Maxillofacial Surgery 12/2011; 41(7):810-3. DOI:10.1016/j.ijom.2011.12.012 · 1.36 Impact Factor