Pulmonary Tuberculosis Mimicking Metastatic Disease in a Patient With Two Previous Primary Malignancies: A Thoracoscopic Diagnostic Challenge.

Pulmonary nodules detected in patients with a history of multiple malignancies are frequently presumed to represent metastatic disease. However, infectious granulomatous disorders, particularly pulmonary tuberculosis, may closely mimic thoracic metastases and create substantial diagnostic challenges. We present the case of a 64-year-old woman with a history of surgically treated renal cell carcinoma and breast cancer who underwent routine thoracic imaging that revealed a pulmonary nodule accompanied by mediastinal lymphadenopathy. Given her oncological history, metastatic disease was considered an important diagnostic possibility. The patient underwent video-assisted thoracoscopic surgery (VATS), including wedge resection of the pulmonary lesion and mediastinal lymph node biopsy. Histopathological examination demonstrated necrotizing granulomatous inflammation composed of epithelioid histiocytes and multinucleated giant cells, without evidence of malignancy. These findings favored an infectious granulomatous process, particularly pulmonary tuberculosis. The patient was subsequently referred to a specialized tuberculosis center for microbiological evaluation and further management. This case highlights the importance of including pulmonary tuberculosis in the differential diagnosis of newly detected pulmonary lesions, even in patients with multiple previous malignancies. It also underscores the limitations of imaging alone and reinforces the essential role of tissue diagnosis in preventing inappropriate cancer staging and unnecessary oncological treatment while facilitating timely disease-specific evaluation and management.