A Case of Lung Adenocarcinoma Metastasized to Follicular Thyroid Carcinoma

The primary aims of the present case report are to: (1) detail the clinical, imaging, and pathological characteristics of a thyroid neoplasm-associated case with complex diagnostic considerations, to highlight key challenges in distinguishing secondary from primary thyroid malignancies; (2) synthesize existing literature on tumor-to-tumor metastasis in thyroid neoplasms, to contextualize current understanding of such rare scenarios; and (3) provide practical insights for clinicians navigating the evaluation and management of similar cases.