AB021. Remission of recurrent pleural thymoma achieved with lenvatinib as a single agent: a case report

Background: Managing pleural disseminated recurrence of thymoma presents significant challenges. Treatment options include systemic chemotherapy, radiotherapy, surgery, or combination therapy. However, there have been limited case reports on the efficacy of targeted inhibitors in metastatic thymoma. Here, we present a case of pleural thymoma recurrence that responded well to single-agent lenvatinib treatment.

Case Description: A 50-year-old male with stage IVa thymoma (histology type B3) underwent neoadjuvant radiotherapy followed by sternotomy and extensive surgery of the tumor, including partial resection of lung, pericardium, diaphragm, and pleural tumors. Although platinum-based systemic chemotherapy was indicated, it was not prescribed due to the patient’s underlying chronic kidney disease [stage 5, estimated glomerular filtration rate (eGFR) <10]. A postoperative boost radiotherapy of 60 Gy over 30 fractions was delivered to the tumor bed. Eleven months later, a follow-up computed tomography (CT) scan revealed large pleural tumors. Given the extent of the disease and previous treatment, resection or radiotherapy was not suggested. Cytotoxic chemotherapy remains the standard pharmacotherapeutic option as systemic treatment; however, the patient was not feasible because of chronic kidney disease. Although multikinase inhibitors such as sunitinib and lenvatinib have shown promise in treating thymic carcinoma, there was limited experience of lenvatinib single agent use for the metastatic thymoma. Despite limited prior reports, we initiated treatment with the multikinase inhibitor lenvatinib at the dose of 20 mg qd. A CT scan done 2 months post treatment showed partial regression of the tumors. So, the treatment with lenvatinib was continued, and a subsequent CT scan in September 2022 (7 months post treatment) indicated complete clinical remission of the tumors. Lenvatinib therapy was continued, and the latest CT scan in April, 2024 did not reveal visible tumors. Our experience with lenvatinib in metastatic thymoma demonstrated a durable remission lasting for 2 years.

Conclusions: Pleural disseminated recurrent thymoma poses a therapeutic challenge with no established standard treatment. A multidisciplinary approach involving surgery, local radiotherapy, systemic chemotherapy, targeted inhibitor therapy, or immunotherapy may offer benefits to patients.

Keywords: Pleural recurrent thymoma; lenvatinib; case report