Ali Javaria, Munawar Shahzeb, Haider Rimsha, Ahmad Ahmad Nawaz, Hashmi Atif A
Pathology, Liaquat National Hospital and Medical College, Karachi, PAK.
Internal Medicine, Liaquat College of Medicine and Dentistry, Karachi, PAK.
Cureus. 2020 Dec 27;12(12):e12321. doi: 10.7759/cureus.12321.
Myoepithelial carcinomas are rare malignant salivary gland tumours encountered most commonly in the parotid gland and are amenable to surgical resection. However, when they occur at complex anatomical locations, complete resection becomes difficult due to their locally aggressive nature. Here we describe a case of a large myoepithelial carcinoma arising in the floor of the mouth and involving major structures at the skull base. A 30-year-old female presented with a slow-growing mass in the oral cavity. Computed tomography (CT) scan showed a heterogeneous appearing lesion in the mouth floor measuring 6.7 x 5.8 x 7.3 cm. Superiorly, the lesion was extending up to the skull base, laterally extending up to the parotid gland and inferiorly up to the submandibular gland. This lesion was also encasing the internal carotid artery. Incisional biopsy under local anaesthesia was performed, and the specimen was sent for histopathological analysis. Microscopic examination showed a neoplastic lesion composed of sheets of cells with oval nuclei and clear cytoplasm with a myxoid background. Immunohistochemical expression of pan-cytokeratin (CKAE1/AE3), p63, anti-smooth muscle actin (ASMA) and glial fibrillary acidic protein (GFAP) supported the diagnosis of myoepithelial neoplasm. The patient then underwent excision of the mass followed by histological analysis, which further showed microscopic evidence of infiltration into the surrounding tissue along with areas of atypia and significant mitoses. These morphological findings supported the diagnosis of myoepithelial carcinoma. The excised tumour was reaching up to the excision margin. Myoepithelial carcinomas are rare malignant tumours with diverse histomorphological patterns frequently present as a diagnostic challenge. The mainstay of treatment is complete surgical excision with disease-free margins, which can be challenging due to local aggressiveness and large size of these tumours. When these tumours occur in complex anatomical locations, complete excision becomes difficult, resulting in a dismal prognosis.
肌上皮癌是一种罕见的恶性涎腺肿瘤，最常见于腮腺，可通过手术切除。然而，当它们发生在复杂的解剖位置时，由于其局部侵袭性，完整切除变得困难。在此，我们描述一例发生于口底并累及颅底主要结构的巨大肌上皮癌病例。一名30岁女性因口腔内缓慢生长的肿块就诊。计算机断层扫描（CT）显示口底有一个大小为6.7×5.8×7.3 cm的异质性病变。病变向上延伸至颅底，向外延伸至腮腺，向下延伸至下颌下腺。该病变还包绕颈内动脉。在局部麻醉下进行了切开活检，并将标本送去进行组织病理学分析。显微镜检查显示肿瘤性病变由成片的细胞组成，细胞核呈椭圆形，细胞质透明，背景为黏液样。全细胞角蛋白（CKAE1/AE3）、p63、抗平滑肌肌动蛋白（ASMA）和胶质纤维酸性蛋白（GFAP）的免疫组化表达支持肌上皮肿瘤的诊断。患者随后接受了肿块切除及组织学分析，结果进一步显示显微镜下有浸润周围组织的证据，伴有异型性区域和大量核分裂。这些形态学表现支持肌上皮癌的诊断。切除的肿瘤切缘阴性。肌上皮癌是罕见的恶性肿瘤，具有多样的组织形态学模式，常常构成诊断挑战。治疗的主要方法是完整手术切除，切缘无肿瘤残留，但由于这些肿瘤的局部侵袭性和体积较大，这可能具有挑战性。当这些肿瘤发生在复杂的解剖位置时，完整切除变得困难，导致预后不佳。
