Thymic carcinoma, initially unresectable, converted to complete resection with pathological complete response following chemotherapy alone.

Abstract

Thymic carcinomas frequently invade adjacent structures, rendering complete surgical resection difficult. Although multimodal treatment strategies, including chemotherapy, radiotherapy, and surgery, are employed, the prognosis of thymic carcinoma remains poor. Furthermore, it is exceedingly rare to achieve a pathological complete response following chemotherapy alone or in combination with radiotherapy. A 69-year-old man presented with an anterior mediastinal tumor. Surgical resection of the tumor was planned for diagnostic and therapeutic purposes. However, chest computed tomography (CT) performed approximately 1 month after the initial CT scan revealed rapid tumor growth from 38 to 52 mm, with suspected invasion into the left upper lobe and left main pulmonary artery. We performed a surgical biopsy for diagnosis, and pathological examination confirmed thymic carcinoma. Since radiation therapy was not feasible because of interstitial pneumonia, the patient received chemotherapy with carboplatin plus paclitaxel. Post-chemotherapy CT revealed tumor shrinkage to 15 mm and a clear border with the left main pulmonary artery. Radical surgery was subsequently performed, and the tumor was resected along with the left upper lobe, mediastinal fat tissue, and pericardium. The resected specimen did not contain any residual tumor cells, indicating a complete pathological response. The patient has remained free of recurrence for two years after surgery. This patient, who initially had an unresectable thymic carcinoma, achieved complete resection in response to chemotherapy with carboplatin and paclitaxel, resulting in a complete pathological response.