Department of Maxillo-Facial Surgery, Hospital of Perugia, Sant'Andrea Delle Fratte, 06132, Perugia, Italy.
Department of Experimental Medicine, Section of Anatomic Pathology and Histology, Medical School, University of Perugia, Perugia, Italy.
Head Neck Pathol. 2021 Dec;15(4):1345-1349. doi: 10.1007/s12105-020-01282-5. Epub 2021 Jan 4.
Myoepithelial carcinoma ex pleomorphic adenoma is defined as a malignant epithelial neoplasm arising from a primary or recurrent benign pleomorphic adenoma. This type of tumor comprises 3.6% of all salivary gland tumors and 12% of malignant ones. Clinically, it most commonly presents as a firm mass in the parotid gland. The development of this neoplasm in the sinonasal and nasopharyngeal regions is extremely rare and only few cases are reported in the literature. The prognosis of myoepithelial carcinoma is variable. Marked cellular pleomorphism, high mitotic rate, and high proliferative activity correspond to a poor prognosis. In this article, the authors report the histopathological features of a clinical case of a 64-years-old patient with a large median maxillary neoplasm diagnosed as myoepithelial carcinoma/ex-pleomorphic adenoma. The tumor was resected and subjected to secondary reconstruction using a revascularized free fibula flap. The myoepithelial derivation of neoplastic cells was demonstrated by immunohistochemical positivity for S-100 protein (strong and diffuse), cytokeratin 14 (strong and diffuse), and GFAP (focal).
多形性腺瘤恶变的肌上皮癌定义为起源于原发性或复发性良性多形性腺瘤的恶性上皮性肿瘤。这种类型的肿瘤占所有唾液腺肿瘤的 3.6%，占恶性肿瘤的 12%。临床上，它最常表现为腮腺内的坚实肿块。这种肿瘤在鼻窦和鼻咽部的发生极为罕见，文献中仅报道了少数病例。肌上皮癌的预后各不相同。明显的细胞多形性、高有丝分裂率和高增殖活性与预后不良相关。本文作者报道了一例 64 岁患者的临床病例，该患者的上颌中线有一个大的肿瘤，诊断为肌上皮癌/多形性腺瘤恶变。肿瘤被切除，并使用带血管游离腓骨瓣进行二次重建。免疫组织化学染色显示 S-100 蛋白（强且弥漫阳性）、细胞角蛋白 14（强且弥漫阳性）和 GFAP（局灶阳性）阳性，证实了肿瘤细胞的肌上皮来源。
