(dtpa-phe(1))-octreotide and Neurofibromatosis-1

A Tc MDP bone superscan occurs when osseous activity is extremely intense and genitourinary and soft tissue activity is not identified. A similar phenomenon has been described with metaiodobenzylguanidine (MIBG) in metastatic pheochromocytoma and neuroblastoma. We present a case of metastatic paraganglioma resulting in an MIBG superscan. Neuroendocrine bone metastasis alters the biodistribution of MIBG such that the liver, heart, and urinary bladder are not well visualized. Our case occurred in association with neurofibromatosis type 1 and in the absence of an identified primary tumor.

Topics: 3-Iodobenzylguanidine; Female; Humans; Middle Aged; Neurofibromatosis 1; Octreotide; Paraganglioma; Pentetic Acid; Radionuclide Imaging; Tomography, X-Ray Computed; Whole Body Imaging

Scintigraphy with the radiolabelled somatostatin analogue indium-111-DTPA-D-Phe-1-octreotide has recently been proposed for the imaging of CNS neoplasms expressing somatostatin receptors. While meningiomas are imaged with high sensitivity, neurinomas do not take up octreotide owing to the lack of somatostatin receptors. Neurofibromatosis is a relatively uncommon disorder in which meningiomas and neurinomas often occur in the same patient. Differential diagnosis between these two tumours by computed tomography and magnetic resonance imaging can be difficult. This study reports on 111In-octreotide scintigraphy in four patients with neurofibromatosis. 111In-octreotide scintigraphy was shown to be very helpful in the in vivo differential diagnosis: all four meningiomas showed intense tracer uptake, while all 15 neurinomas were negative (P < 0.001 by Fisher's exact test). It may be concluded that scintigraphy with 111In-octreotide is a useful diagnostic procedure in neurofibromatosis, complementing standard neuroradiological imaging procedures.

Topics: Adolescent; Child; Diagnosis, Differential; Female; Humans; Indium Radioisotopes; Male; Middle Aged; Neurofibromatosis 1; Neurofibromatosis 2; Octreotide; Pentetic Acid; Radionuclide Imaging