Case Report: Complete remission of thymic carcinoma using dose-dense chemotherapy.

Thymic epithelial tumors, including thymoma and thymic carcinoma, are rare malignancies of the mediastinum, often associated with poor long-term outcomes in advanced stages. Surgical resection and platinum-based chemotherapy have been the cornerstone of management for resectable and advanced, unresectable disease, respectively, with the use of neoadjuvant chemotherapy alone or chemotherapy combined with radiation in specific cases. We report the case of a patient diagnosed with advanced hormone receptor-positive/HER2-positive breast cancer and a synchronous, advanced thymic carcinoma. After completion of standard-of-care adjuvant dose-dense chemotherapy for her breast cancer, interval imaging revealed marked reduction in the size of the thymic mass with subsequent surgical resection noting a complete pathologic response. The patient remained disease-free for four years before developing recurrence of the thymic carcinoma. This case highlights the potential effectiveness of dose-dense chemotherapy in the treatment of thymic malignancies. Locally advanced and metastatic thymic carcinoma remains challenging to manage, making this patient's response particularly noteworthy. Given that the therapeutic strategies for thymic tumors have remained largely unchanged in recent years, dose-dense chemotherapy may represent a promising addition to the current treatment paradigm, though further investigation is needed to evaluate its broader applicability.