Imaging advances in the diagnosis of endocrine neoplasia.

Endocrine neoplasms are rare tumors that have traditionally been imaged with ultrasound, CT, magnetic resonance imaging, and angiography. Additional imaging modalities are now available. Endoscopic ultrasound is a new imaging approach to islet cell tumors of the pancreas, in which they typically appear round, homogeneous, and slightly hypoechoic compared with the pancreatic parenchyma. Carcinoid tumors can now be localized with 111In octreotide scintigraphy, which binds to the somatostatin receptors in the tumor. Pheochromocytomas have a distinctive appearance on magnetic resonance imaging, but important advances have occurred using 131I metaiodobenzylguanidine (MIBG). 131I MIBG scanning has a high diagnostic accuracy in detecting pheochromocytoma, with sensitivity greater than 90%. The various tumors and recent advances in their imaging are discussed.