Visualization of a recurrent carcinoid tumor and an occult distant metastasis by technetium-99m-sestamibi.

We present a case of atypical carcinoid that showed avid uptake of sestamib in a recurrent bronchial carcinoid tumor and a solitary, unsuspected, occult, bony metastatic lesion in the distal femur. As carcinoid tumors are known to be vascular, we suspect that its avidity for sestamibi is secondary to increased blood flow, although other factors such as the transmembrane potentials of plasma and mitochondrial membranes and relative number of mitochondria present in the cells of this carcinoid tumor, may have also played a role.