Multiple lung metastases from typical type A thymoma after long-term follow-up: a case report

BACKGROUND: Typical type A thymomas are slow-growing tumors generally associated with a favorable clinical course, and distant metastasis is exceedingly rare. CASE PRESENTATION: We report a case of multiple lung metastases from a typical type A thymoma in a 74-year-old man, identified 9 years after the initial detection of an anterior mediastinal nodule. The patient underwent simultaneous thymectomy and wedge resection of the pulmonary nodule. Histopathological examination confirmed a diagnosis of typical type A thymoma with pulmonary metastases. Postoperatively, the patient was also diagnosed with prostate cancer as a secondary malignancy. At 2-year follow-up, without any postoperative treatment, there was no evidence of progression or development of new pulmonary lesions. CONCLUSION: This case underscores the potential for distant metastasis in patients with otherwise indolent, typical type A thymomas, highlighting the need for long-term surveillance.