Pleural Metastasis

The goal of this observational study is to explore the effectiveness of electrocautery resection combined with hyperthermic intrathoracic chemotherapy (HITHOC) in patients with thymic epithelial tumors with pleural metastasis or recurrence. The study aims to: * Evaluate whether this combined treatment improves event-free survival in patients with pleural metastasis from thymic epithelial tumors * Assess the rates of grade ≥3 treatment-related adverse events * Examine how this treatment affects patients' quality of life Participants will: * Undergo extended thymectomy with electrocautery resection of pleural metastases * Receive two cycles of hyperthermic intrathoracic chemotherapy with cisplatin and doxorubicin at 42-43°C, 2-4 days apart * Complete quality of life questionnaires (EQ-5D) at baseline and regular intervals * Have regular follow-up visits with imaging and clinical assessments for up to 36 months to monitor for disease recurrence or progression