General Thoracic Surgery.
Department of Diagnostic Pathology, Kindai University Nara Hospital, Ikoma.
Medicine (Baltimore). 2021 Feb 5;100(5):e24491. doi: 10.1097/MD.0000000000024491.
The relationship between thymic tumors and Sjögren syndrome (SjS) is unknown, and surgical resection has not been optimized. Especially, thymic carcinoma with autoimmune disease is rare. Analysis of SS-A52, germinal centers, plasma cells, and Foxp3+ Treg in thymic carcinoma has never been reported, and their pathological roles in causing SjS have not been studied.
A 78-year-old man presented with sputum production and xerostomia while asleep. Chest computed tomography showed a homogeneous and hypodense mass in the anterosuperior mediastinum. Serum levels of the antinuclear antibody, antibody to SS-A, and antibody to SS-B were positive.
Thymic carcinoma (squamous cell carcinoma) and SjS.
Video-assisted thoracoscopic resection of the mediastinal tumor and postoperative radiation therapy was performed.
The histological diagnosis was thymic squamous cell carcinoma. Histologically, the squamous carcinomatous cells were arranged in nests and cords in the fibrohyaline stroma with capsular invasion. In the stroma, dense lymphoid tissues containing large reactive germinal centers and many plasma cells were also noted. In the involuted thymus, CD20-positive mature lymphocytes infiltrated, and germinal centers were noted. Double immunohistochemical staining revealed that SS-A52 antigen was positive in both the carcinoma component and CD20-positive mature B cells. Postoperatively, the xerostomia persisted, and serum SS-A and SS-B remained positive. No evidence of carcinoma recurrence with chest computed tomography scan was observed at 18-months follow-up.
In the surgical treatment of thymic tumors with SjS, extended thymectomy might be worth considering to stop the progressive destruction of the targets of SjS-specific autoantibodies. However, the postoperative symptoms may not dramatically improve because the target organs might have changed irreversibly, and memory B cells might persist. This is the first report that demonstrated the SS-A52 antigen presentation in a thymic tumor to the best of our knowledge.
胸腺瘤与干燥综合征（SjS）之间的关系尚不清楚，手术切除也未得到优化。特别是伴自身免疫性疾病的胸腺癌较为罕见。分析胸腺癌中的 SS-A52、生发中心、浆细胞和 Foxp3+Treg 尚未见报道，其导致 SjS 的病理作用也尚未研究。
一名 78 岁男性，出现咳痰和睡眠时口干。胸部计算机断层扫描显示前上纵隔均质和低密度肿块。血清抗核抗体、抗 SS-A 抗体和抗 SS-B 抗体阳性。
胸腺癌（鳞状细胞癌）和 SjS。
行电视辅助胸腔镜纵隔肿瘤切除术和术后放疗。
组织学诊断为胸腺癌（鳞状细胞癌）。组织学上，鳞状癌巢状和索状排列于纤维透明基质中，伴有包膜侵犯。在基质中，还可见密集的淋巴组织，其中含有大反应性生发中心和许多浆细胞。在退化的胸腺中，CD20 阳性成熟淋巴细胞浸润，并有生发中心。双免疫组织化学染色显示，SS-A52 抗原在癌成分和 CD20 阳性成熟 B 细胞中均为阳性。术后口干持续存在，血清 SS-A 和 SS-B 仍为阳性。18 个月随访时，胸部计算机断层扫描未见癌复发证据。
在 SjS 合并胸腺瘤的手术治疗中，扩大胸腺切除术可能值得考虑，以阻止 SjS 特异性自身抗体靶器官的进行性破坏。然而，由于靶器官可能已经发生不可逆转的变化，且记忆 B 细胞可能持续存在，术后症状可能不会显著改善。据我们所知，这是首次报道胸腺癌中 SS-A52 抗原的呈递。
