St. Elizabeth's Medical Center, Tufts University School of Medicine Brighton, MA
Padmavathi D. Srivoleti, MD1, Erik Holzwanger, MD2, Rohit Dhingra, MD2, Sandeep Krishnan, MBBS, PhD1; 1St. Elizabeth's Medical Center, Tufts University School of Medicine, Brighton, MA; 2Tufts University Medical Center, Boston, MA
Introduction: Pancreatic neuroendocrine tumors (p-NET) continue to increase in prevalence with increased usage of cross-sectional abdominal imaging. Annual incidence of p-NET in the United States is about 4-5 cases per million. Phenotypically, p-NET can be either purely solid, solid cystic or purely cystic. Purely cystic p-NET are extremely rare. Endosonographically, cystic p-NETs are often characterized by thickened walls, nodularity and septations. We present here an exceedingly rare case of a purely cystic p-NET.
Methods: An 81-year-old man, with history of prostate cancer on Leuprolide, type II diabetes mellitus, atrial fibrillation presented for CT abdomen/pelvis for radiotherapy mapping. He had about a 30-pound unintentional weight loss and decreased appetite in the preceding 6 months. He denied steatorrhea, jaundice or abdominal pain. He is a former smoker with 30 pack years and consumes alcohol thrice a week. CT abdomen/pelvis was remarkable for a right renal lesion. For further evaluation, MRI was done which showed an incidental, T2 hyperintense cystic lesion in pancreatic body measuring 1.7 cm x 1.9 cm. The main pancreatic duct was prominent, though did not appear to be abnormally dilated. Endoscopic ultrasound (EUS) performed with a linear echoendoscope revealed a 1.7 cm x 2 cm cystic lesion with septations in the pancreatic body with a thick wall and no intra mural nodules. There was no distinct communication with the main pancreatic duct. Pancreatic duct had normal endosonographic appearance. Fine needle aspiration performed for cytology was positive for synaptophysin and chromogranin A, suggestive of grade I neuroendocrine neoplasm (Mitoses 0/10 HPF, Ki-67 index 1%). Pancreatic fluid amylase was 249 U/L and CEA was 6 ng/ml (Normal < 4.7). He is currently planned for surgical resection of the lesion. Discussion: Pancreatic neuroendocrine tumors are rare tumors. While most p-NETs present as solid, homogenous tumors, 13-17% of p-NETs may present as cystic lesions. Purely cystic p-NET are exceedingly rare and present as common cystic lesions, such as pseudocysts or mucinous cystic neoplasms. Additionally, low CEA and non-functioning tumors pose an added diagnostic challenge. Thus, it is imperative to endoscopically ultrasound and biopsy these lesions for diagnosis. While management is usually surgical, there is mounting evidence that conservative management of purely cystic p-NET may be an option given their low biological aggressiveness and more favorable prognosis.
Figure 1: MRI image showing T2 hyperintense cystic lesion in pancreatic body measuring 1.7 cm x 1.9 cm. The main pancreatic duct appears prominent, though does not appear to be abnormally dilated
Figure 2: . Endoscopic ultrasound (EUS) image showing 1.7 cm x 2 cm multicystic lesion in the pancreatic body with a thick wall and no intra mural nodules.
Disclosures: Padmavathi Srivoleti indicated no relevant financial relationships. Erik Holzwanger indicated no relevant financial relationships. Rohit Dhingra indicated no relevant financial relationships. Sandeep Krishnan indicated no relevant financial relationships.