Lack of utility of (111)In-pentetreotide scintigraphy in localizing ectopic ACTH producing tumors: follow-up of 18 patients.
Octreotide scintigraphy has been advocated as the principal imaging modality for localizing ectopic ACTH-secreting tumors in Cushing's syndrome. To assess its usefulness we reviewed the course of 18 consecutive patients with ectopic ACTH-producing tumor. Imaging included (111)In-pentetreotide scintigraphy, computed tomography (CT), and/or magnetic resonance imaging (MRI). Tumor was detected initially in 7/18 patients, and in 3/18 during follow-up. No ACTH-secreting tumor was detected by octreotide scintigraphy when CT/ MRI were negative. Seventeen of forty octreotide scintigrams were abnormal. CT and/or MRI confirmed tumors in 10, but demonstrated nonendocrine lesions in association with 6 false positive octreotide scintigrams. Hepatic venous sampling for ACTH refuted one lesion detected by octreotide and CT scans. Twenty-three of forty octreotide scintigrams were normal. Of these, 8 were false negative, as CT and/or MRI detected tumor; 10 agreed with negative CT and MRI, and 5 correctly refuted false positive CT and/or MRI scans. Repeated CT/ MR, but not octreotide scintigraphy, led to tumor resection in 2 patients. We conclude that octreotide scintigraphy does not offer greater sensitivity than CT/MRI and that false positive scans are common. Although octreotide scintigraphy may be helpful in selected cases, it is not a significant advance over conventional imaging for ectopic ACTH-secreting tumors.
Torpy
D J
DJ
Developmental Endocrinology Branch, National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, Maryland 20892, USA.
Chen
C C
CC
Mullen
N
N
Doppman
J L
JL
Carrasquillo
J A
JA
Chrousos
G P
GP
Nieman
L K
LK
D000182:ACTH Syndrome, Ectopic / Q000000981:diagnostic imaging* / Q000628:therapy; D000328:Adult; D000368:Aged; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D007205:Indium Radioisotopes; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged; D011877:Radionuclide Imaging; D012189:Retrospective Studies; D013004:Somatostatin / Q000031:analogs & derivatives*; D014057:Tomography, X-Ray Computed; D016896:Treatment Outcome
D007205:Indium Radioisotopes; D013004:Somatostatin; C081788:pentetreotide