In-111 octreotide, a somatostatin analog, has been used for detecting gastrinomas, insulinomas, glucagonomas, apudomas, carcinoids, medullary thyroid carcinomas, lung carcinomas, as well as other malignacies. The case presented is that of a 76-year-old woman with a history of recurrent gastrointestinal bleeding. Endoscopy showed a gastric ulcer. A secretin stimulation test showed positive results and serum gastrin levels were markedly elevated. An In-111 octreotide scan demonstrated increased mediastinal uptake. On thoracotomy, the lesion was identified as a substernal goiter.