title: Combined use of 111In-labeled pentetreotide and three-step immunoscintigraphy with antichromogranin A monoclonal antibody in the diagnosis of pituitary adenomas.
abstract: For various pituitary adenomas, it has been demonstrated that somatostatin receptor can be present. Pilot studies have shown that radio-indium labeled pentetreotide allows very good scintigraphic localization of somatostatin receptor-bearing cell masses. Recently, the presence of CgA in pituitary adenomas has also been demonstrated. MAb A11, raised against CgA, has been successfully used with a three-step ISG for the diagnosis of neuroendocrine tumors. Therefore the combined use of three-step ISG with MAb A11 and radiolabeled somatostatin can be useful in the diagnosis of pituitary adenomas. Twelve patients, 5 secreting (group A) and 7 nonsecreting (group B) pituitary adenomas, were enrolled in the study. All patients underwent three-step ISG, and, 2 wk later, scintigraphy with 111In-labeled pentetreotide (Octreoscan). Three-step ISG consisted of i.v. injection of 1 mg of biotinylated MAb A11 (first step), followed by 10 mg of avidin (second step) and [99mTc]PnAO-biotin (third step). Tomographic imaging were acquired for three-step ISG and Octreoscan at 2 and 4 h after radiotracer injection, respectively. The results are the following: 2 patients of group A (secreting tumors) had a positive three-step ISG, whereas all the patients but one of the same group had a positive pentetreotide study; all the patients of group B (nonsecreting tumors) had a positive three-step ISG and 4 had a positive pentetreotide scintigraphy. These data suggest the utility of the combined use of these techniques for a better diagnosis of pituitary adenomas.
authors.affiliation: INB-CNR, DIBIT, IRCCS H S. Raffaele, Milan, Italy.
authors.forename: P
authors.initials: P
authors.lastname: Magnani
authors.forename: G
authors.initials: G
authors.lastname: Paganelli
authors.forename: A G
authors.initials: AG
authors.lastname: Siccardi
authors.forename: C
authors.initials: C
authors.lastname: Songini
authors.forename: P
authors.initials: P
authors.lastname: Colombo
authors.forename: G
authors.initials: G
authors.lastname: Faglia
authors.forename: F
authors.initials: F
authors.lastname: Fazio
mesh_terms: D000236:Adenoma / Q000000981:diagnostic imaging*; D000293:Adolescent; D000368:Aged; D000911:Antibodies, Monoclonal; D002648:Child; D053379:Chromogranin A; D002864:Chromogranins / Q000276:immunology*; D005260:Female; D006801:Humans; D007205:Indium Radioisotopes; D008297:Male; D010911:Pituitary Neoplasms / Q000000981:diagnostic imaging*; D016719:Radioimmunodetection; D013004:Somatostatin / Q000031:analogs & derivatives
chemical_list: D000911:Antibodies, Monoclonal; D053379:Chromogranin A; D002864:Chromogranins; D007205:Indium Radioisotopes; D013004:Somatostatin; C081788:pentetreotide