Pancreatic accessory spleen. False positive with 99mTc-Octreotide.

The case is presented on a patient with abdominal pain and suspicion of neuroendocrine tumor in the tail of the pancreas shown in the abdominal CT and MRI. Whole-body scintigraphy and abdominal SPECT/CT with 99mTc-octreotide were performed that showed a nodular lesion partially on the posterior side of the pancreas tail. This nodule showed faint tracer uptake, and was reported as probable neuroendocrine tumor. Partial pancreatectomy and splenectomy were performed, and the histological study identified the lesion as an ectopic spleen. There are similar cases in the literature that match these findings, but this lesion is still frequently diagnosed after performing unnecessary surgery. When an asymptomatic intrapancreatic mass is detected, an accessory spleen should be considered and specific diagnostic techniques should be performed, such as labeled and denatured red blood cell SPECT/CT.