Posterior mediastinal nodule diagnosed as a tuberculous granuloma infiltrating into the aorta

Although tuberculous infection rarely results in aortic aneurysm formation or rupture, its precursor lesion has never been identified in cases with tuberculosis. We incidentally encountered a case of a posterior mediastinal nodule with concomitant chest computed tomography (CT) findings of multiple pulmonary micronodular shadows. Since an enlargement of the mediastinal nodule was retrospectively apparent, we considered the lesion as malignant. Enhanced CT showed luminal irregularity in the descending aorta, located adjacent to the nodule, in addition to the disappearance of the fat plane between the lesion and the aorta. We successfully resected the nodule with the aorta under partial cardiopulmonary bypass. Based on the pathological and postoperative bacterial findings, the nodule was diagnosed as a tuberculous granuloma infiltrating into the medial layer of the aorta.