Presurgical diagnosis of a primary carcinoid tumor of the thymus with MIBG.

A primary carcinoid tumor of the thymus showing ectopic ACTH syndrome was evaluated scintigraphically with four radiopharmaceuticals and a fluorescence method. Iodine-123-MIBG and 201Tl-Cl scintigraphy clearly demonstrated the tumor. Gallium-67-citrate and 99mTc(V)-DMSA showed no tumor uptake. The fluorescence method confirmed numerous storage granules of norepinephrine. Iodine-123-MIBG scintigraphy could be useful in the presurgical diagnosis of carcinoid tumors of the thymus.