The correct answer to the question What is the most likely diagnosis of this incidental finding? is answer 3: Coronary artery fistula, arising from the circumflex artery, supplying a residual pulmonary lesion post-tuberculosis.

The CT coronary angiogram reveals a coronary artery fistula arising from the circumflex artery, anastomosing with hypertrophic bronchial arteries. This vascular cluster supplies a nodular mass in the left suprahilar region without FDG uptake on PET/CT (Fig. 1). This patient had a history of tuberculosis treatment in her youth, and retrospective imaging confirms this nodular mass has been present ever since.

Multipanel image showing 3D reconstruction of the coronary arteries, chest CT and PET/CT