Tc-99m sestamibi uptake in the chest mimicking a malignant lesion of the breast

The use of nuclear medicine imaging of the breast has resulted in the improved diagnosis of breast cancer (Radiology 196 (1995) 421; J. Nucl. Med. 36 (1995) 1758). Itʹs use is becoming more widespread, particularly as breast optimized scintigraphy with a high-resolution, breast-specific gamma camera has been developed (J. Nucl. Med. 43 (2002) 909; J. Nucl. Med. 45 (2004) 553). With the increasing use of breast-optimized scintigraphy, pitfalls in the interpretation of breast-optimized scintigraphy are being recognized. This report describes a previously unrecognized cause for a false positive interpretation of scintimammography due to tumor uptake of the radiotracer in the chest as a result of physiologic activity in the auricular aspect of the right atrium.