False-Negative Neuroendocrine Tumor Identified With 68Ga-DOTATOC PET/CT: A Case of Well-Differentiated Somatostatinoma.

Abstract

We report the case of a 25-year-old man who was undergoing follow-up for neurofibromatosis type 1. The man underwent 68Ga-DOTATOC PET/CT for a suspected well-differentiated duodenal neuroendocrine tumor. This examination did not reveal any significant uptake, whereas complementary 18F-FDG PET/CT showed moderate 18F-FDG uptake in the primary tumor as well as the adenopathy. Histology, a well-differentiated duodenal neuroendocrine tumor was confirmed, consistent with the diagnosis of somatostatinoma. Although rare, this well-differentiated neuroendocrine tumor should be kept in mind as a possible source of false-negative somatostatin receptor PET/CT findings.