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Solid pseudopapillary tumour should be part of differential diagnosis of focal pancreatic lesions with increased 18 F‐FDOPA uptake
Author(s) -
Somme François,
MontazRosset MarieSoline,
Averous Gerlinde,
Deur Jeanne,
Goichot Bernard,
Bachellier Philippe,
Addeo Pietro,
Imperiale Alessio
Publication year - 2020
Publication title -
clinical endocrinology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.055
H-Index - 147
eISSN - 1365-2265
pISSN - 0300-0664
DOI - 10.1111/cen.14202
Subject(s) - medicine , magnetic resonance imaging , serous cystadenoma , neuroendocrine tumors , radiology , nuclear medicine , differential diagnosis , pancreas , positron emission tomography , somatostatin receptor , serous fluid , pathology , somatostatin
Objective To assess the specificity of increased 18 F‐dihydroxyphenylalanine ( 18 F‐FDOPA) uptake in patients who underwent PET/CT for suspicion of isolated pancreatic neuroendocrine tumour (pNET). False‐positive results mimicking a pNET have been investigated. Material and methods Carbidopa‐assisted 18 F‐FDOPA PET/CT scans performed in patients with suspicion of localized pNET were retrieved. Only patients with a definitive diagnosis were retrospectively included. When available, the histopathological result after pancreatic surgery was the gold standard. In other cases, the diagnosis was based on endoscopic ultrasonography (EUS)/cytology and/or on concordant imaging results of at least two of the following: contrast‐enhanced computed tomography (CE‐CT), magnetic resonance imaging (MRI) and somatostatin receptor scintigraphy (SRS). Results Forty‐four among 731 patients were selected. Among these, 36 patients (82%) were surgically treated, revealing pNET (n = 28), solid pseudopapillary tumour (SPT) (n = 4), adenocarcinoma (n = 2), serous cystadenomas (n = 1) and solitary fibrous tumour (n = 1) cases. An additional three cases of pNET were diagnosed by EUS/cytology. In the remaining five patients, a consensus was reached on follow‐up imaging results: pNET (n = 1), serous cystadenoma (n = 2) and undetermined/no pNET (n = 2). Both specificity and negative predictive value of 18 F‐FDOPA PET/CT for localized pNET were 67%. Surprisingly, all four false‐positive results were SPTs showing intense 18 F‐FDOPA uptake and negative SRS. There was no significant difference in 18 F‐FDOPA uptake intensity between PET‐positive pNETs and SPTs. Conclusion 18 F‐FDOPA PET/CT is not specific for pNET in patients with localized pancreatic lesions. SPT could mimic pNET and should be part of differential diagnosis in such a clinical situation. If these results are confirmed in a broader population, the imaging pattern 18 F‐FDOPA PET‐positive/SRS‐negative lesions might be considered as the imaging phenotype of SPT.