European Journal of Hybrid Imaging (May 2021)

18F-FDG PETCT and 68Ga-DOTA PETCT mismatch with in vivo histopathological characterization of low-grade neuroendocrine pancreatic tumor

  • Marcello Moro Queiroz,
  • Carlos Diego Holanda Lopes,
  • Alessandra Corte Real Salgues,
  • Felipe de Galiza Barbosa,
  • Emerson Shigueaki Abe,
  • Thales Parenti Silveira,
  • Marcel Cerqueira Cesar Machado,
  • Fernanda Cunha Capareli

DOI
https://doi.org/10.1186/s41824-021-00103-4
Journal volume & issue
Vol. 5, no. 1
pp. 1 – 6

Abstract

Read online

Abstract Background Pancreatic neuroendocrine tumor (PNET) is a subgroup of neuroendocrine tumor (NET) that has unique biology and natural history. The histological classification has a major role in the management of this pathology, but in recent years Gallium 68 dotatate (68Ga-DOTA) scanning is at the center of a discussion about how these imaging technologies can modify clinical management of neuroendocrine tumors and how their results are correlated to Ki67 index. Method We hereby describe a case of a patient that investigated an unspecific stable pancreatic nodule suspected of high-grade NET after evaluation with 68Ga-DOTATOC positron emission tomography—computed tomography (PETCT) and 18F-Fluorodeoxyglucose (18F-FDG) PETCT. Results The images corroborate the hypothesis of high-grade NET based on the standard uptake value (SUV) described in both image exams (16.4 in 18FDG PETCT and 9.2 in 68Ga-DOTATOC PETCT). After surgery, the histopathological analyses revealed a localized grade 2 well-differentiated NET, Ki-67 of 4.7, glucose transport proteins 1 (GLUT1) negative by immunohistochemistry, evidencing a rare case of mismatch between the functional image and the in vivo characterization of the neoplasm. Conclusion Functional imaging of neuroendocrine tumors with different modalities of PETCT is a well-described strategy for evaluating PNET and can dictate conducts in some cases. However, histopathological analysis is crucial to confirm the grade and prognosis related to this disease.

Keywords