Gun Banu Dogan, Ozdamar Sukru Oguz, Bahadir Burak, Uzun Lokman
Department of Pathology, Zonguldak Karaelmas Universitesi Tip Fakultesi, Patoloji Anabilim Dali, 67600 Kozlu, Zonguldak, Turkey.
Ear Nose Throat J. 2009 Jul;88(7):1005-9.
Salivary gland tumors that display myoepithelial differentiation exclusively or predominantly are relatively uncommon, and the assessment of malignancy in a myoepithelial tumor can be difficult. We report a case of parotid gland myoepithelioma composed predominantly of spindle cells with focal capsular invasion. The patient was a 65-year-old woman who presented with a painless mass in the right preauricular region. Histologically, the tumor had a solid and multinodular growth pattern and was predominantly made up of spindle cells with a minor component of epithelioid cells with moderate cellular atypia. Focal regions of tumor cells infiltrated the capsule with tongue-like processes, but tumor infiltration into the adjacent parotid tissue was absent. The tumor cells showed strong cytoplasmic immunoexpression of vimentin, pankeratin, S-100 protein, and smooth-muscle actin. Immunostains with glial fibrillary acidic protein, melanoma marker, epithelial membrane antigen, and carcinoembryonic antigen were negative. Expression of p53 was observed focally in the nuclei of the tumor cells. A final diagnosis of salivary gland myoepithelioma with focal capsular invasion was made, and the case was regarded as a myoepithelial tumor of uncertain malignant potential. In this report, we discuss the histologic criteria required to diagnose malignancy in salivary gland myoepithelial tumors.
仅表现为肌上皮分化或主要表现为肌上皮分化的涎腺肿瘤相对少见，对肌上皮肿瘤进行恶性程度评估可能存在困难。我们报告1例主要由梭形细胞构成且有局灶性包膜侵犯的腮腺肌上皮瘤。患者为65岁女性，表现为右耳前区无痛性肿块。组织学上，肿瘤呈实性及多结节生长模式，主要由梭形细胞组成，有少量上皮样细胞，细胞有中度异型性。肿瘤细胞呈舌状突起浸润包膜的局灶区域，但未浸润至相邻腮腺组织。肿瘤细胞波形蛋白、全角蛋白、S-100蛋白及平滑肌肌动蛋白呈强细胞质免疫表达。胶质纤维酸性蛋白、黑色素瘤标志物、上皮膜抗原及癌胚抗原免疫染色均为阴性。肿瘤细胞核内局灶性观察到p53表达。最终诊断为伴有局灶性包膜侵犯的涎腺肌上皮瘤，该病例被视为恶性潜能不确定的肌上皮肿瘤。在本报告中，我们讨论了诊断涎腺肌上皮肿瘤恶性程度所需的组织学标准。
