I-123 MIBG Uptake in a Gastrointestinal Stromal Tumor (GIST)

I-123 metaiodobenzylguanidine (MIBG) scintigraphy is the examination of choice for visualizing tumor sites of pheochromocytoma. We report a middle-aged woman with incomplete Carney's Triad (association of pheochromocytoma/paraganglioma, gastrointestinal stromal tumor [GIST], and pulmonary chondromas) in whom a GIST was identified on the basis of its MIBG uptake. She had undergone surgical resection of a pheochromocytoma and postoperatively developed a mass in the epigastrium, which was thought to be recurrence. The lesion was MIBG-positive. However, following surgery, histologic examination of the specimen revealed findings suggestive of GIST.