Somatostatin receptor scintigraphy for early detection of regional and distant metastases of medullary carcinoma of the thyroid

Three patients are described who had regional and distant metastases of med ullary thyroid cancer detected by somatostatin receptor scintigraphy but no t by CT; two had minimal disease that was amenable to surgery. The first pa tient had been followed for 2 years before having a repeated scan and posit ive CT, with subsequent surgical removal of metastatic paratracheal nodes. The plasma calcitonin level, however, did not approach normal values after surgery, and a third scan showed persistence of focal uptake in the left pa ratracheal area of the lower neck, whereas CT was negative. At repeated exp loration, a tumor mass of medullary carcinoma, embedded iii lymphatic tissu e, was removed. Nine months after the last surgical procedure, calcitonin a nd carcinoembryonic antigen levels were normal. The second patient underwen t microdissection of the mediastinum and removal of two metastatic nodes th at were demonstrable only by the scintigraphic technique. The plasma calcit onin level subsequently became normal. The third patient, with multiple end ocrine neoplasia IIB and associated pheochromocytoma, had bony metastatic i nvolvement of the left shoulder, demonstrable initially on somatostatin rec eptor scintigraphy and subsequently with radioiodinated metaiodobenzylguani dine but not on CT.