Diagnosis of a remote neuroendocrine tumor thrombus by EUS-guided FNA.

Case report

A 67-year-old man presented with left upper-quadrant abdominal pain and weight loss. A CT scan demonstrated the presence of a 3.7 cm hypoenhancing mass arising from the tail of the pancreas (Fig. 1) and possible multifocal disease at the head of the pancreas (Fig. 2). A subsequent fluorodeoxyglucose (FDG) positron emission tomography (PET)-CT scan demonstrated possible FDG activity in the pancreatic head and increased FDG activity within the distal pancreatic tail. Upper EUS identified a hypoechoic mass in the pancreatic tail measuring 35 mm, corresponding with the CT scan findings (Fig. 3). FNA was performed, and the result of cytologic analysis of the specimen was positive for a well-differentiated pancreatic neuroendocrine tumor. No pancreatic head mass was identified on EUS to correspond to the PET-CT scan.

Figure 1

CT scan of the abdomen demonstrating an ill-defined mass in tail of pancreas (red arrow).

Figure 2

CT scan of the abdomen demonstrating a possible multifocal disease at head of pancreas (red arrow).

Figure 3

Upper EUS demonstrating a 3.3- × 2.6 -cm hypoechoic mass in tail of pancreas.

The patient was subsequently referred to our pancreas surgery team for possible resection. Before pursuing resection, the surgery team requested a DOTATATE PET scan to further investigate for multifocal disease. This study demonstrated the presence of the known lesion in the tail of the pancreas (Fig. 4). There was no evidence of distant metastatic disease and, specifically, no evidence of disease involving the pancreatic head or portomesenteric confluence.

Figure 4

DOTATATE PET CT demonstrating activity in pancreatic tail (arrow).

Given persistent concerns based on the original imaging studies, the surgery team requested that we repeat the upper EUS with a goal of sampling the pancreatic head and/or thrombus to rule out metastatic disease.

Procedure

Upper EUS with FNA of splenic vein thrombus was performed (Video 1, available online at www.VideoGIE.org).

The previously described round mass was again identified in the pancreatic tail. Endosonographic examination revealed the presence of a single thrombus measuring 4 cm, which extended from the portal vein into the splenic vein (Figure 5, Figure 6). No mass was seen at the head of the pancreas. Numerous venous collaterals were seen surrounding the head and neck of the pancreas (Fig. 7). FNA of the thrombus was performed for cytologic analysis. Color Doppler imaging was used before needle puncture to confirm a lack of significant vascular structures within the needle path. After a safe trajectory was identified, 4 passes were made with the 22-gauge FNA needle (Fig. 8). There were no signs of any bleeding after completion of the procedure. Rapid on-site examination by a cytotechnologist confirmed specimen adequacy and provided a preliminary diagnosis of tumor thrombus.

Figure 5

Endosonographic visualization of thrombus adjacent to head of pancreas.

Figure 6

Endosonographic image of the portomesenteric confluence from the body of the stomach with thrombus localized to the splenic vein. SMV, Superior mesenteric vein; PV, portal vein; SV, splenic vein.

Figure 7

Endosonographic view of venous collaterals overlying thrombus near head of pancreas.

Figure 8

Endosonographic view of a 22-gauge FNA needle entering the thrombus.

Outcome

Final FNA cytologic analysis of the thrombus demonstrated that the neoplastic cells were positive for synaptophysin and chromogranin, supporting the diagnosis of a malignant neuroendocrine tumor thrombus (Fig. 9). Given the presence of metastatic disease, a curative resection was not possible. Our group has previously reported a series of successful cases of EUS-guided FNA of remote tumor thrombi. This case demonstrates the utility and safety of performing EUS-guided FNA of a possible tumor thrombus. Differentiation of a tumor from a bland thrombus can have a meaningful impact on a patient’s clinical course.

Figure 9

H & E stain demonstrating neoplastic cells.

Disclosure

Dr Iyer is a consultant for Medtronic, Pentax Medical, and Symple Surgical and the recipient of funding from Exact Sciences, Medtronic, Pentax Medical, and Nine Point Medical. Dr Marya is a consultant for AnX Robotica. All other authors disclosed no financial relationships relevant to this publication.