Dedifferentiation in salivary gland carcinomas

American Journal of Surgical Pathology (Impact Factor: 4.59). 04/2000; 24(3):469-71. DOI: 10.1097/00000478-200003000-00018
Source: PubMed
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    ABSTRACT: Dedifferentiated epithelial-myoepithelial carcinoma (DEMC) is very rare salivary gland neoplasm with only anecdotal reports. We present an analysis of DEMC, based on a case and review of literature. Our patient, an 85-year-old woman, presented with a submandibular mass of 5 years duration that was increasing in size over a 5-week period. Histologically, there were areas of typical epithelial-myoepithelial carcinoma, with dedifferentiation of both components, manifesting morphologically as salivary duct carcinoma and areas of myoepithelial carcinoma. A review of literature revealed 21 previously reported cases of DEMC. DEMC occurs at an average age of 72 years, most often in the parotid gland (72%) followed by submandibular gland (17%). Dedifferentiation more often involves the epithelial component (13/15 cases) than the myoepithelial component (5/15 cases). Although typical epithelial-myoepithelial carcinomas are fairly indolent (average disease-free survival of 11.34 years), dedifferentiation confers a poor prognosis (survival reported from 1 to 72 months).
    International Journal of Surgical Pathology 12/2012; 21(5). DOI:10.1177/1066896912468153 · 0.96 Impact Factor
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    ABSTRACT: "Dedifferentiation" and/or high-grade transformation (HGT) has been described in a variety of salivary gland carcinomas, including acinic cell carcinoma, adenoid cystic carcinoma, epithelial-myoepithelial carcinoma, polymorphous low-grade adenocarcinoma, myoepithelial carcinoma, low-grade mucoepidermoid carcinoma and hyalinizing clear cell carcinoma, although the phenomenon is a rare event. Recent authors tend to preferably use the term HGT instead of "dedifferentiation" in these cases. HGT-tumors are composed of conventional carcinomas juxtaposed with areas of HG morphology, usually either poorly differentiated adenocarcinoma or "undifferentiated" carcinoma, in which the original line of differentiation is no longer evident. The HG component is generally composed of solid nests, sometimes occurring in cribriform pattern of anaplastic cells with large vesicular pleomorphic nuclei, prominent nucleoli and abundant cytoplasm. Frequent mitoses and extensive necrosis is evident. The Ki-67 labeling index is consistently higher in the HG component. p53 abnormalities have been demonstrated in the transformed component in a few examples, but the frequency varies by the histologic type. HER-2/neu overexpression and/or gene amplification is considerably exceptional. The molecular-genetic mechanisms responsible for the pathway of HGT in salivary gland carcinomas largely still remain to be elucidated. Salivary gland carcinomas with HGT have been shown to be more aggressive than conventional carcinomas with a poorer prognosis, accompanied by higher local recurrence rate and propensity for cervical lymph node metastasis, suggesting the need for wider resection and neck dissection.
    Head and Neck Pathology 07/2013; 7(Suppl 1). DOI:10.1007/s12105-013-0458-8
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    ABSTRACT: Summary. A case of high-grade epithelial carcinoma arising in a low-grade epithelial-myoepithelial carcinoma of the parotid gland is described. The patient was a 52 year-old male who presented a parotideal lump of approximately 20 mm in diameter and underwent excisional surgery. Histologically a typical low-grade epithelial myoepithelial carcinoma was evidenced and, in its context, an area of 7 x 4 mm showing focal aspects of a high-grade adenocarcinoma. The immunohistochemical pattern of the ductal epithelial cells of the low-grade component was similar to that of the epithelial cells of the high-grade carcinoma. The Ki-67 labelling index of the epithelial-myoepithelial carcinoma was 5%, whereas that of the high-grade lesion was 30%. EGFR, p53 and HER-2 genes seem to play no role in the biological behaviour of the tumour, as well as p16CDKN2A, BRAF, NRAS and C-KIT genes studied with biomolecular methods in both the highgrade and low-grade components. No local recurrence occurred after surgery, but multiple bone, cutaneous and lung metastases were detected 10 months later. The patient died 19 months after diagnosis.
    European Journal of Oncology 10/2013; 18(2):103-109. · 0.22 Impact Factor