This is a case of striking radioiodine and [99mTc]pertechnetate uptake by disseminated nonthyroidal (gastric) adenocarcinoma. A 65-yr-old man was euthyroid and serum thyroglobulin concentration was normal at 11 ng/ml. Bone-marrow biopsy showed that the metastatic tumor cells were negative for thyroglobulin on immunoperoxidase stain and the secretory product was mucicarmine-positive. We estimate that radioiodine uptake in the normal thyroid gland was less than 10% of total tumor uptake. At

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... y, the stomach was the site of the primary tumor, which had the same cellular and histochemical characteristics as the metastatic lesions in bone and liver. It is emphasized that the use of pertechnetate for screening patients with gastric adenocarcinoma may be clinically useful in the early detection of metastatic lesions.