Detection of occult thymoma during exercise thallium 201, technetium 99m tetrofosmin imaging for coronary artery disease

Thallium (Tl) 201 and technetium (Tc) 99m tetrofosmin single-photon emissio n CT are routinely used in the evaluation of coronary artery disease. Media stinal tumors demonstrate Tl 201 and Te 99m tetrofosmin uptake. We report a 56-year-old man who developed chest pain after a previously successful ang ioplasty and stent of the left anterior descending coronary artery. He unde rwent a Tl 201, Tc 99m tetrofosmin exercise study. Abnormal mediastinal act ivity was visualized in both the Tl 201 and Tc 99m tetrofosmin images. Subs equently, the patient underwent resection of a stage II thymoma. Unanticipa ted focal extracardiac accumulation during myocardial scintiscanning should lead to further investigation to exclude mediastinal tumor.