Al Masri Manar, Pirgousis Phillip, Bhatt Alok A, Reynolds Jordan, Riegert-Johnson Douglas, Agarwal Shweta
Department of Laboratory Medicine and Pathology, Mayo Clinic, 4500 San Pablo Road, Jacksonville, FL, 32224, USA.
Department of Otolaryngology- Head & Neck Surgery, Mayo Clinic, Jacksonville, FL, USA.
Head Neck Pathol. 2025 Sep 8;19(1):108. doi: 10.1007/s12105-025-01840-9.
Myoepithelial carcinoma (MECA) is a malignant neoplasm composed exclusively of myoepithelial cells and accounts for less than 1% of all salivary gland tumors. Its diagnosis is often challenging due to histologic overlaps with benign lesions and its variable morphologic presentation. Although molecular profiling has emerged as a valuable tool in salivary gland tumor classification, the genetic landscape of MECA remains incompletely defined. We report a case of a 65-year-old male with a history of chronic lymphocytic leukemia who presented with otalgia, sore throat, and dysphagia, ultimately diagnosed with a high-grade MECA of the submandibular gland following excision. Preoperative imaging revealed extensive regional lymphadenopathy and likely metastases to the lungs and ribs, and next-generation sequencing (NGS) identified a RET p.V804M variant, well-known to be pathogenic in medullary thyroid carcinoma but previously unreported in MECA. After this genetic change was subsequently found to be germline, this finding expands the implications for the breadth of RET as a tumor driver, particularly given the patient's older age at presentation, with RET alterations in salivary tumors most commonly associated with genetic fusion events.
肌上皮癌（MECA）是一种仅由肌上皮细胞组成的恶性肿瘤，占所有涎腺肿瘤的比例不到1%。由于其组织学表现与良性病变重叠且形态学表现多样，其诊断往往具有挑战性。尽管分子谱分析已成为涎腺肿瘤分类中的一种有价值的工具，但MECA的基因图谱仍未完全明确。我们报告一例65岁男性，有慢性淋巴细胞白血病病史，出现耳痛、咽痛和吞咽困难症状，切除术后最终诊断为下颌下腺高级别MECA。术前影像学检查显示广泛的区域淋巴结肿大，可能已转移至肺部和肋骨，二代测序（NGS）鉴定出一种RET p.V804M变异，该变异在甲状腺髓样癌中已知具有致病性，但此前在MECA中未见报道。在随后发现这种基因改变为种系突变后，这一发现扩展了RET作为肿瘤驱动因素的影响范围，特别是考虑到患者就诊时年龄较大以及涎腺肿瘤中的RET改变最常与基因融合事件相关。
