Peter E Humphrey1,2, Francesco Alessandrino3, Andrew M Bellizzi4,5, Koenraad J Mortele6,7. 1. Northwest Imaging, Kalispell Regional Medical Center, Kalispell, MT, 59901, USA. 2. Division of Abdominal Imaging and Intervention, Department of Radiology, Brigham & Women's Hospital, Harvard Medical School, Boston, MA, 02115, USA. 3. Division of Body MRI, Department of Radiology, Beth Israel Deaconess Medical Center, Harvard Medical School, 330 Brookline Avenue, Ansin 224, Boston, MA, 02215, USA. 4. Department of Pathology, University of Iowa Carver College of Medicine, Iowa City, IA, 52242, USA. 5. Department of Surgical Pathology, Brigham & Women's Hospital, Harvard Medical School, Boston, MA, 02115, USA. 6. Division of Abdominal Imaging and Intervention, Department of Radiology, Brigham & Women's Hospital, Harvard Medical School, Boston, MA, 02115, USA. kmortele@bidmc.harvard.edu. 7. Division of Body MRI, Department of Radiology, Beth Israel Deaconess Medical Center, Harvard Medical School, 330 Brookline Avenue, Ansin 224, Boston, MA, 02215, USA. kmortele@bidmc.harvard.edu.
Abstract
PURPOSE: To evaluate the multimodality imaging features of non-hyperfunctioning pancreatic endocrine tumors (NF-PNET) with histopathological correlation. METHODS: Preoperative imaging (CT: n = 23; MRI: n = 14; (111)In-octreotide: n = 8) of 28 patients (17 female; mean age 55 years) with resected NF-PNET were evaluated for tumor location, size, morphology, attenuation/signal intensity, (111)In-octreotide uptake, cystic degeneration, and enhancement. Tissue specimens were assessed for the extent of stromal fibrosis, vascular density, presence of a fibrous pseudocapsule, and tumor grading. Correlation between imaging and histopathology was made using the Fisher-Freeman-Halton exact test. RESULTS: NF-PNET arose from the pancreatic head/neck (n = 10), body (n = 7), and tail (n = 11). On CT, NF-PNET (mean largest diameter: 4.4 cm) appeared predominantly solid (69.6%), well defined (91.3%), and oval (47.8%) in shape. In the late arterial phase, NF-PNET appeared mainly hypovascular (55.5%). Septations (30.4%) and calcifications (21.7%) were relatively uncommon. On MRI, NF-PNET (mean size: 2.6 cm) appeared most commonly as solid (57.1%), encapsulated (71.4%), oval (64.2%) lesions that were hyperintense on T2-WI (64.3%), and hypo- or isovascular to pancreas (66.7%) during the late arterial phase. Cystic NF-PNET (3.8 cm) were not significantly larger than solid (3.5 cm) NF-PNET (CT, p = 0.758; MRI, p = 0.451). (111)In-octreotide uptake was demonstrated in 5/8 (62.5%) patients. At histopathology, NF-PNET were predominantly encapsulated (69.2%); stromal fibrosis comprised <33% of the tumor (69.2%), and vascular density was average (46.1%). A significant association was demonstrated between the degree of fibrosis and hypointensity on T2-WI (p = 0.003). Vascular density, tumor grade, and degree of fibrosis did not significantly relate to the pattern of enhancement. CONCLUSIONS: NF-PNETs have variable imaging appearances but are most commonly oval shaped, solid, and well-defined/encapsulated masses, and hypovascular on late arterial and portal venous phase. Cystic degeneration in NF-PNET appears independent of tumor size. Low signal intensity on T2-WI correlates with extensive intratumoral fibrosis.
PURPOSE: To evaluate the multimodality imaging features of non-hyperfunctioning pancreatic endocrine tumors (NF-PNET) with histopathological correlation. METHODS: Preoperative imaging (CT: n = 23; MRI: n = 14; (111)In-octreotide: n = 8) of 28 patients (17 female; mean age 55 years) with resected NF-PNET were evaluated for tumor location, size, morphology, attenuation/signal intensity, (111)In-octreotide uptake, cystic degeneration, and enhancement. Tissue specimens were assessed for the extent of stromal fibrosis, vascular density, presence of a fibrous pseudocapsule, and tumor grading. Correlation between imaging and histopathology was made using the Fisher-Freeman-Halton exact test. RESULTS: NF-PNET arose from the pancreatic head/neck (n = 10), body (n = 7), and tail (n = 11). On CT, NF-PNET (mean largest diameter: 4.4 cm) appeared predominantly solid (69.6%), well defined (91.3%), and oval (47.8%) in shape. In the late arterial phase, NF-PNET appeared mainly hypovascular (55.5%). Septations (30.4%) and calcifications (21.7%) were relatively uncommon. On MRI, NF-PNET (mean size: 2.6 cm) appeared most commonly as solid (57.1%), encapsulated (71.4%), oval (64.2%) lesions that were hyperintense on T2-WI (64.3%), and hypo- or isovascular to pancreas (66.7%) during the late arterial phase. Cystic NF-PNET (3.8 cm) were not significantly larger than solid (3.5 cm) NF-PNET (CT, p = 0.758; MRI, p = 0.451). (111)In-octreotide uptake was demonstrated in 5/8 (62.5%) patients. At histopathology, NF-PNET were predominantly encapsulated (69.2%); stromal fibrosis comprised <33% of the tumor (69.2%), and vascular density was average (46.1%). A significant association was demonstrated between the degree of fibrosis and hypointensity on T2-WI (p = 0.003). Vascular density, tumor grade, and degree of fibrosis did not significantly relate to the pattern of enhancement. CONCLUSIONS: NF-PNETs have variable imaging appearances but are most commonly oval shaped, solid, and well-defined/encapsulated masses, and hypovascular on late arterial and portal venous phase. Cystic degeneration in NF-PNET appears independent of tumor size. Low signal intensity on T2-WI correlates with extensive intratumoral fibrosis.
Authors: P Mapelli; C Bezzi; D Palumbo; C Canevari; S Ghezzo; A M Samanes Gajate; B Catalfamo; A Messina; L Presotto; A Guarnaccia; V Bettinardi; F Muffatti; V Andreasi; M Schiavo Lena; L Gianolli; S Partelli; M Falconi; P Scifo; F De Cobelli; M Picchio Journal: Eur J Nucl Med Mol Imaging Date: 2022-02-14 Impact factor: 10.057
Authors: Milica Mitrovic-Jovanovic; Nikica Grubor; Stefan Milosevic; Aleksandra Jankovic; Katarina Stosic; Slavenko Ostojic; Aleksandar Ninic; Marjan Micev; Jelena Djokic Kovac Journal: Diagnostics (Basel) Date: 2022-04-15