Department of Pathology at the University of Texas, MD Anderson Cancer Center, Houston 77030, TX, USA.
Department of Pathology at the University of Texas, MD Anderson Cancer Center, Houston 77030, TX, USA.
Hum Pathol. 2019 Jan;83:100-105. doi: 10.1016/j.humpath.2018.08.027. Epub 2018 Sep 12.
Seven primary thymic epithelial neoplasms, 3 thymomas and 4 thymic carcinomas, with rhabdomyomatous component are herein described. The patients are 2 women and 5 men between the ages of 42 and 62 years (average, 52 years). Clinically, the patients presented with nonspecific symptoms of cough, chest pain, and dyspnea. None of the patients had history of myasthenia gravis or of previous malignancy. Diagnostic imaging revealed the presence of an anterior mediastinal mass in all the patients. Surgical resection was accomplished in all the cases. The 3 thymoma cases were encapsulated tumors: histologically, 2 were lymphocyte rich (World Health Organization type B1), and 1 was an atypical thymoma (World Health Organization type B3). All the thymic carcinomas were ill-defined tumor masses with infiltrative borders and histologically were high-grade carcinomas. In each tumor, in different proportion, there were easily identifiable areas with rhabdomyomatous component characterized by larger cells with eosinophilic cytoplasm and eccentrically placed nuclei. Immunohistochemical stains in all cases showed clearly demarcated presence of the epithelial component (keratin positive/desmin and myoglobin negative) and the rhabdomyomatous component (desmin and myoglobin positive/keratin negative). The 3 patients with thymoma are alive and without recurrence 3 and 5 years after surgical resection, whereas 3 patients with carcinoma died between 2 and 3 years after surgical resection. One patient with thymic carcinoma was lost to follow-up. The current cases highlight the ubiquitous distribution of myoid cells in different types of thymic epithelial neoplasms.
本文描述了 7 例原发性胸腺上皮肿瘤，包括 3 例胸腺瘤和 4 例胸腺癌，均具有横纹肌样成分。患者为 2 名女性和 5 名男性，年龄 42 岁至 62 岁（平均 52 岁）。临床上，患者表现为咳嗽、胸痛和呼吸困难等非特异性症状。所有患者均无重症肌无力病史或先前恶性肿瘤病史。诊断性影像学检查显示所有患者均存在前纵隔肿块。所有病例均行手术切除。3 例胸腺瘤为包膜肿瘤：组织学上，2 例为淋巴细胞丰富型（世界卫生组织 B1 型），1 例为非典型胸腺瘤（世界卫生组织 B3 型）。所有胸腺癌均为边界不清的肿瘤肿块，具有浸润性边界，组织学上为高级别癌。在每个肿瘤中，都有不同比例的横纹肌样成分，其特征为具有嗜酸性细胞质和偏心核的较大细胞。所有病例的免疫组织化学染色均清楚地显示上皮成分（角蛋白阳性/结蛋白和肌红蛋白阴性）和横纹肌样成分（结蛋白和肌红蛋白阳性/角蛋白阴性）的明确存在。3 例胸腺瘤患者在手术后 3 年和 5 年时均存活且无复发，而 3 例胸腺癌患者在手术后 2 年至 3 年内死亡。1 例胸腺癌患者失访。目前的病例强调了肌样细胞在不同类型的胸腺上皮肿瘤中的广泛分布。
