Dopamine-producing paraganglioma not visualized by iodine-123-MIBG scintigraphy.

A patient with an aorticopulmonary paraganglioma was found to have normal plasma norepinephrine and epinephrine levels and elevated dopamine levels. Iodine-123-MIBG scintigraphy did not visualize this tumor. The same finding on a negative MIBG scan in two patients with exclusively dopamine-secreting chemodectomas has been previously reported. In our patient, [111In-DTPA-D-Phe1]-octreotide scintigraphy proved to be an effective imaging technique.