Pancreatic serous cystadenoma with a high ⁶⁸Ga DOTATOC-uptake mimicking a pancreatic NET

Abstract

Introduction: 68 Ga-DOTATOC positron emission tomography (PET) has replaced octreotide scintigraphy as method of choice in detecting and staging most neuroendocrine tumors (NETs). With a better signal-tonoise ratio and improved spatial resolution, sensitivity is increased. However, several non-NETs express surface somatostatin receptors, challenging the positive predictive value of a DOTATOC scan regarding a NET diagnosis. This is of particular concern in pancreas as NET is a frequent differential diagnosis, as is a variety of cystic neoplasms increasingly often diagnosed as incidental findings.Case Report: A 66-year-old man was diagnosed with an asymptomatic cystic tumor in the pancreatic neck. At computed tomography scan (CT) a 4 cm P-NET was suspected as an incidental finding. The diagnosis was supported by a positive 68 Ga-DOTATOC scan, with a high DOTATOC-uptake in the pancreatic tumor and in a local interaortocaval node. The tumor was radically resected. At pathologic examination a pancreatic serous cystadenoma (SCN) was unexpectedly diagnosed, with

Increased Uptake in Microcystic Serous Cystadenoma Mimicking Pancreatic Neuroendocrine Tumor on 68Ga-DOTATATE PET/MRI

“…This indicates that PET/CT is helpful in the diagnosis of pancreatic neuroendocrine tumor when tumor uptake of 68 Ga-DOTA somatostatin analogs is observed. But false-positive results can also occur, as demonstrated by serous cystadenoma of the pancreas with 68 Ga-DOTATOC PET/CT uptake, as reported previously 5–7 . The current case showed that a pancreatic serous cystadenoma may display moderate 68 Ga-DOTATATE uptake at the edge of the lesion on PET/MRI.…”

“…But false-positive results can also occur, as demonstrated by serous cystadenoma of the pancreas with 68 Ga-DOTATOC PET/CT uptake, as reported previously. [5][6][7] The current case showed that a pancreatic serous cystadenoma may display moderate 68 Ga-DOTATATE uptake at the edge of the lesion on PET/MRI. The superior soft-tissue resolution of MRI is able to reveal the high fluid content of serous cystadenoma, especially in DWI.…”

Microcystic Serous Cystadenoma Masquerading as Pancreatic Neuroendocrine Tumor on 99mTc-HYNIC-TOC SPECT/CT

“…3,4 Similarly, a few case reports, using somatostatin receptor PET imaging, showed increased tracer uptake in microcystic serous cystadenoma. [5][6][7][8] The case indicates that microcystic serous cystadenoma can show increased 99m Tc-HYNIC-TOC uptake and should be included in the differential diagnosis of 99m Tc-HYNIC-TOC-avid pancreatic masses.…”