ABSTRACT
Primary thymic adenocarcinoma is a very rare malignancy of the anterior mediastinum with no standardized treatment. A 36-year-old male patient presented with hoarseness over the past 3 months. A chest computed tomography (CT) scan showed an infiltrative mass to the proximal vessels and aortic arch in left upper mediastinum (4.1x3.1x5.4 cm). Brain magnetic resonance imaging (MRI) showed focal lesions, suggesting metastasis in the left frontal lobe. A thoracoscopic biopsy of the mediastinal mass confirmed a primary thymic adenocarcinoma forming a glandular structure with atypia of tumor cells. The patient received four cycles of systemic chemotherapy, consisting of etoposide and cisplatin, with concurrent radiotherapy (6,000 cGy/30 fractions) to the mediastinal lesion and the metastatic brain lesion (4,200 cGy/12 fractions). A follow-up chest CT scan and brain MRI showed a decrease in the size of the left upper mediastinal mass and brain lesion. We report a rare case of the primary thymic adenocarcinoma with a literature review.