EUS FNA of a Pancreatic Neuroendocrine Tumor
Comments: A 67 year old man was referred for an EUS of an incidental pancreatic mass lesion.
His past medical history included a colorectal cancer resected 18 year ago. He was admitted to the hospital 1 month prior to the EUS for one episode of melaena. He had no weight loss and was otherwise well. He had a normal gastroscopy and colonoscopy and a capsule endoscopy showed a small bowel polyp. To further investigate this polyp the patient had a CT abdomen that did not show the polyp but that revealed a 1.6 cm well defined mass in the neck of the pancreas (figure 1,2).
On EUS a well defined 1.6 cm homogenous hypoechoic mass with a central calcification was seen in the neck of the pancreas. The pancreatic duct was mildly dilated in the body and tail. There were no enlarged lymph nodes and the liver was normal. Fine needle aspiration biopsy was performed using a 25FG needle ( 3 passes) (video1 ). The cytological smears were highly cellular with discohesive sheets of small cells with high nuclear:cytoplasmic ratio, limited eccentric cytoplasm, round to pleiomophic nucleai and a mix of fine and coarse cromatin (figure 3). These features were suggestive of a neuroendocrine tumor. On immuno-histochemistry the cells were CAM5.2, pankeratin (weak), chromogranin and synaptophysin positive and cytokeratin 7, cytokeratin 20, cytokeratin 5/6 and S100 negative (figure 4). These findings confirmed the diagnosis of a pancreatic neuroendocrine tumour. The patient underwent a somastostatin receptor scintigraphy that showed a solitary increased uptake in the neck of the pancreas. Currently the patient is awaiting surgery.
EUS is an excellent method of diagnosing NET with an accuracy between 83%-93% (1,2) The typical EUS appearance of NET is that of a well defined round, homogeneous, hypoechoic lesion within the pancreas. Calcifications may suggest the presence of psammoma bodies, pathognomonic for somatostatinoma (3). Rarely, NET may also appear isoechoic or cystic, the cystic NET representing 8% in recently published series (4). The most helpful cytologic finding for the diagnosis of NET is a richly cellular sample with a monotonous, poorly cohesive population of small or medium-sized cells with granular chromatin and plasmacytoid morphology (5).
1. Anderson M.A., Carpenter S., Thompson N.W., et al: Endoscopic ultrasound is highly accurate and directs management in patients with neuroendocrine tumors of the pancreas. Am J Gastroenterol 95. 2271-2277.2000
2. Ardengh J.C., Andrade de Paulo G., et al: EUS-guided FNA in the diagnosis of pancreatic neuroendocrine tumors before surgery. Gastrointest Endosc 60. 378-384.2004
3. Patel K. K, Kang Kim M. Neuroendocrine tumors of the pancreas: endoscopic diagnosis.
Curr Opin Gastroenterol. 2008;24(5):638-642.
4. Jani N, Khalid A, Kaushik N, et al. EUS-guided FNA diagnosis of pancreatic endocrine tumors: new trends identified. Gastrointest Endosc 2008; 67:44-50.
5. Chatzipantelis P, Salla C , et all. Endoscopic Ultrasound-guided Fine-Needle Aspiration Cytology of Pancreatic Neuroendocrine Tumors : A Study of 48 Cases. Cancer, 2008, vol. 114, no4, pp. 255-262
| Contributed by: |
Alina Stoita, MBBS Advanced Trainee in Gastroenterology St Vincent's Hospital Sydney, Australia David Williams, MBBS Head of Department of Gastroenterology St Vincent's Hospital Sydney, Australia |
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Citation: Stoita, MBBS, A. & Williams, MBBS, D. (Nov 20 2009). EUS FNA of a Pancreatic Neuroendocrine Tumor. The DAVE Project. Retrieved Feb, 8, 2010, from http://daveproject.org/viewfilms.cfm?film_id=886 Times viewed since Feb 2006: 1301 |
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