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

Inclusion Criteria:

• Pathologically confirmed thymic epithelial tumor (TET)
• Imaging evidence of thymic epithelial tumor with pleural dissemination or recurrence, deemed suitable for HITHOC by multidisciplinary thoracic team
• Age ≥16 years and ≤80 years
• American Society of Anesthesiologists (ASA) physical status classification I-II
• Normal major organ function
• No history of other malignancies
• Prior chemotherapy completed >4 weeks, radiotherapy >6 weeks, immunotherapy >6 weeks before enrollment
• No allergy to cisplatin or doxorubicin
• Able to understand the study content and provide informed consent

Exclusion Criteria:

• Evidence of extrathoracic metastasis on imaging or pathological examination
• Myasthenia gravis in unstable phase or acute exacerbation
• Severe systemic comorbidities, such as active infection, poorly controlled diabetes, coagulopathy, bleeding tendency, or ongoing thrombolytic/anticoagulation therapy
• Positive serum pregnancy test or lactation (females)
• History of organ transplantation (including autologous bone marrow transplantation and peripheral blood stem cell transplantation)
• History of peripheral nervous system disease, significant psychiatric disorder, or central nervous system disease
• Currently participating in other clinical trials

Adults aged 16-80 years with pathologically confirmed thymic epithelial tumors (thymoma or thymic carcinoma) with pleural dissemination or recurrence, suitable for electrocautery resection and hyperthermic intrathoracic chemotherapy as determined by multidisciplinary team.