Long-term survival in thymic carcinoma with postoperative pl
A 42-year-old woman presented with a mediastinal tumor and anterior chest pain. Computed tomography (CT) revealed a right anterior mediastinal tumor measuring 7.0 × 4.2 × 3.2 cm. CT-guided core-needle biopsy was performed. Since the tumor had been diagnosed as thymoma and estimated to be resectable at initial surgery, she underwent en bloc resection of the tumor and entire thymus gland through a full median sternotomy. Pathological examination revealed that the tumor was moderately differentiated thymic squamous cell carcinoma (SCC), which showed atypical cells varying in size and shape and proliferating in a sheet-like pattern.

Immunohistochemical staining for PAX8, CD5, c-KIT, TdT, and CD1a also demonstrated features that are characteristic of thymic carcinoma. The tumor was graded as pT2 N0 M0, p-Stage II according to the Union for International Cancer Control TNM eighth edition classification. During the third postoperative year, a follow-up CT demonstrated multiple nodules in the right thoracic cavity, which were characteristics of pleural dissemination. The author resected all visible nodules on the visceral pleura except for a nodule with firm adhesions located on the anterior chest wall. The author administered four courses of systemic chemotherapy with carboplatin and etoposide and delivered definitive RT at a dose of 60 Gy directly to the nodule. The patient developed rheumatic arthritis (RA) over the course of this treatment. During the tenth postoperative year, a follow-up CT revealed two nodules in the right thoracic cavity (Fig. 2B, C). We selected RT over surgical resection due to previous intraoperative findings in this patient. RT at a dose of 60 Gy was delivered to each of the nodules. During the 16th postoperative year, a follow-up CT revealed another pleural nodule, which was resected through a horizontal incision made just above the lesion.

Histopathological examination of the resected pleural nodule confirmed establishing a similar diagnosis of thymic squamous cell carcinoma. Immunohistochemical staining for Ki-67 revealed that the proliferation of tumor cells gradually increased. Immunohistochemical staining for p53 and programmed death-ligand 1 (PD-L1 using 22C3 anti-PD-L1 antibody) in the primary tumor and this nodule demonstrated that both were positive for wild-type TP53 and PD-L1. Twenty-five months following the last surgery, the patient remained in good health. No new lesions were noted. Her RA is well controlled with medication.