EUS Recognition and Diagnosis of Cystic NET Script

Video Case Series Slide – [no voiceover]

Disclaimer Slide – [no voiceover]

Official Title Slide – We present a video series to demonstrate techniques for endoscopic ultrasound diagnosis of cystic pancreatic neuroendocrine tumors. EUS-FNA cytology identified neuroendocrine tumor in all cases. The diagnosis was confirmed with surgical pathology.

Disclosures Slide – [no voiceover]

Keywords Slide – [no voiceover]

Case 1 DH Intro – The patient is a 60-year-old male with a history of hepatitis C who presented with abdominal pain and abnormal liver function tests.

Case 1 DH CT scans –The abdominal CT detected 2.8 centimeter cyst in the body of the pancreas with enhancement of the cyst wall, as demarcated by the red arrow. The patient was referred for EUS.

Case 1 DH Video 1 –EUS imaging identified a diffusely thickened hypoechoic cyst wall, up to 5 mm, with a central anechoic fluid.

Case 1 DH Video 2 – Doppler study identifies the absence of flow in the cyst and the needle path.

Case 1 DH Video 3 – The thickened cyst wall is targeted for FNA in order to maximize probability of obtaining a diagnostic cytology sample. Although a 22-gauge needle is typically used for cyst fluid aspiration, a25-gauge needle works well to target a thickened cyst wall and obtain a cellular sample. The needle is moved within the wall without entering the central fluid portion. There is often limited cellularity within the fluid. Repeat sampling of the fluid with the same needle should be avoided to reduce infection risk.

Case 1 Cytology –Cyst fluid aspiration alone provides a less cellular sample and is characterized by low CEA levels (<5) with cystic neuroendocrine tumors, which in isolation typically suggest a non-mucinous cyst, without malignant potential. In cytology, dyscohesive groups of tumor cells with eccentrically located nuclei, indicative of cystic neuroendocrine tumors, are seen. Some tumor cells have fine cytoplasmic vacuoles.

Case 2 GM Intro – The patient is a 75-year-old male who presented with a left lung lower lobe infiltrate and was referred for a chest MRI. A pancreatic lesion was found and the patient was referred for an abdominal MRI for better imaging of the lesion.

Case 2 GM MRI Scan – The abdominal MRI detected a 1.2 centimeter cyst in the tail of the pancreas, as demarcated by the red arrow. The patient was referred for EUS.

Case 2 GM Video 1/2–EUS identifies lobulated anechoic cyst. A diffusely thickened wall which is more hypoechoic than the surrounding pancreas parenchyma, measuring 4 mm is identified.

Case 2 GM Video 3 – Doppler study excludes the presence of blood vessels.

Case 2 GM Video 4 – A 25-gauge needle is used to target the cyst wall and a cellular sample consistent with neuroendocrine tumor was seen on onsite cytology. An additional pass was made for cell block for immunohistochemical staining.

Case 3 TM Intro – The patient is a 61-year-old male who presented with right flank pain and hematuria. The patient was referred for a CT scan of the abdomen.

Case 3 TM CT scans – The abdominal CT detected a 3 centimeter cyst in the tail of the pancreas, as demarcated by the red arrow. The patient was referred for EUS.

Case 3 TM Still – On EUS an anechoic cyst is seen with hypoechoic thickening of the superior portion of the wall.

Case 3 TM Video 1 – Doppler study excludes the presence of blood vessels.

Case 3 TM Video 2–After Doppler study, the nodular portion of the cyst wall is targeted for FNA with a 25-gauge needle. A second pass is made with a 22-gauge needle to drain the cyst fluid and obtain additional sampling of the thickened wall.

Case 4 TL Intro–The patient is a 60-year-old male who presented with routine lower back pain and was referred for a CT of the abdomen.

Case 4 TL CT scan – The abdominal CT detected a 2 centimeter cyst in the neck of the pancreas, as demarcated by the red arrow. The patient was referred for EUS.

Case 4 TL Still 1 – On EUS, multiple hyperechoic septationsare seen within the cyst, with a thickness between 1.5 to 2.5 mm, a thickness greater than typically seen with serous cystadenomas.

Case 4 TL Still 2 – From another angle with EUS, a pancreas side-branch is seen coursing towards the cyst, which is more typical of a side-branch IPMN.

Case 4 TL Video 1/2–The cyst appears differently depending on the angle from which it is viewed with EUS.In addition to measuring the cyst diameter, the thickness of the cyst wall and septations should be measured as well.

Case 4 TL Video 3 - Doppler should be used to determine presence of blood vessels around the cyst.

Case 4 TL Video 4 – After Doppler study, a thickened septation and the cyst wall are targeted for FNA. Repeat sampling of a septation is seen here.Cytology was diagnostic of a cystic neuroendocrine tumor.

Case 5 TR Intro – The patient is a 63-year-old male who was referred for a CT of the abdomen for restaging of melanoma.

Case 5 TR CT Scan – The abdominal CT detected a 1.2 centimeter cyst in the head of the pancreas, as demarcated by the red arrow. Melanoma may metastasize to the pancreas. The patient was referred for EUS.

Case 5 TR Video 1–On EUS, the cyst wall is mildly prominent, at 1.5 mm; however, it is less prominent than on prior cases.

Case 5 TR Video 2/3– After FNA of the wall with a 25-gauge needle, there was self-limited hemorrhage within the cyst, seen as hyperechoic material within the cyst as shown here. Doppler was performed to assess for vascularity and no ongoing bleeding was seen. A second pass with a 22-gauge needle was performed to drain the cyst fluid and obtain additional sampling of the cyst wall.

Technique Highlights Slide – Technique highlights: Give prophylactic intravenous antibiotics, typically 400 mg ciprofloxacin, prior to procedure. Evaluate the thickness of the cyst wall and septations, use Doppler flow to identify and avoid blood vessels and the pancreas duct, and target the thickened wall and septations during FNA. Start with a 25-gauge needle and use capillary technique. Slowly pull the stylet while moving the needle at the target site.If cellularity is low on site, use 10 mL of suction. 22-gauge needles with 10 mL of suction can be used to aspirate the cyst fluid in combination with targeting the wall.

Conclusions –Cystic neuroendocrine tumors typically have low cyst fluid CEA levels. Thickened cyst walls should be recognized and targeted for FNA to maximize cytological diagnosis.

Appendix – A summary of characteristics of cystic pancreatic neuroendocrine tumors from case series of Ho and Yoon are presented for review.