Patient is a 59 yrs old asian male, active smoker, without any significant past medical history, presented with dysnea and chest pain. He was evaluated for coronary artery disease with treadmill exercise stress test. He underwent one day rest – stress myocardial perfusion imaging with Tc-99m Sestamibi.

The SPECT images do not show any reversible myocardial perfusion defects to suggest presence of exercise induced myocardial ischemia. The gated images showed normal left ventricular wall motion with an ejection fraction of 50%.

Incidentally seen is a large intensely active mediastinal mass. This finding was further evaluated by a CT scan which showed a large anterior mediastinal mass.

This was removed by mini sternotomy and pathology revealed a thymoma, measuring 8.0 x 7.5 x 5.5 cms. No morphological features suggestive of malignancy were found in any sections.

Increased tc-99m tetrofosmin uptake in a mediastinal tumor during myocardial perfusion imaging. Vijayakumar V, Soloff E, Rahman AM. Clin Nucl Med. 2004 Jun;29(6):390-1.

Focal uptake of radioactive tracer in the mediastinum during SPECT myocardial perfusion imaging. Chadika S, Kokkirala AR, Giedd KN, Johnson LL, Giardina EG, Bokhari S. J Nucl Cardiol. 2005 May-Jun;12(3):359-61.