Endoscopic ultrasound-guided gold fiducial marker placement for intraoperative identification of insulinoma

Insulinomas are the most common functioning pancreatic neuroendocrine neoplasm, comprising 30 % – 45 % of these tumors. Although laparoscopic resection is safe, minimally invasive, and is associated with shorter length of hospital stay, tumor localization at surgery can be challenging. We describe endoscopic ultrasound (EUS)-guided fiducial placement as a new technique for intraoperative localization of pancreatic insulinoma.

A 36-year-old woman with episodes of confusion that resolved with intake of glucose and whose laboratory tests were suggestive of insulinoma was referred for laparoscopic distal pancreatectomy. Linear-array EUS (GF-UCT 240; Olympus Corp., Center Valley, Pennsylvania, USA) confirmed a tail mass ([Fig. 1]). After retracting the stylet of the fine-needle aspiration (FNA) needle (Expect 19-gauge Flex needle; Boston Scientific Corp., Natick, Massachusetts, USA) by 2 cm, one gold fiducial (3 × 0.8 mm; Best Medical International, Springfield, Virginia, USA) was back-loaded into the lumen of the needle and sealed with bone wax. At EUS, the fiducials were deployed within the tumor by advancing the stylet forward ([Fig. 2]). Overall, two fiducials were deployed ([Fig. 3]), and a preoperative computed tomography (CT) scan confirmed their position. At laparoscopy, the fiducials were identified using cross-table fluoroscopy ([Fig. 4]), and distal pancreatectomy with splenectomy was performed. A frozen section confirmed negative tumor margins, and the explant specimen revealed the tumor with fiducials in place ([Fig. 5]). Final pathological analysis revealed T1 N0 grade II pancreatic neuroendocrine neoplasm ([Fig. 6]).

Fig. 1 Linear-array endoscopic ultrasound (EUS) image of the isoechoic mass lesion in the tail of pancreas, superior to the left kidney.

Fig. 2 Fluoroscopic image showing the linear-array echoendoscope with the 19-gauge fine-needle aspiration (FNA) needle and the first fiducial.

Fig. 3 Endoscopic ultrasound (EUS) image showing the markers within the lesion casting an acoustic shadow (arrow).

Fig. 4 Intraoperative fluoroscopic image with the stapler gun in place. The two fiducial markers can be easily visualized.

Fig. 5 Postoperative specimen of the pancreas, showing the fiducial marker within the lesion.

Fig. 6 Postoperative histological specimen showing uniform sheets of polyhedral cells with hyperchromatic nuclei and abundant eosinophilic cytoplasm, consistent with a neuroendocrine neoplasm (hematoxylin and eosin stain, × 40).

Preoperative injection of India ink [1] or indocyanine green [2] under EUS guidance was developed to facilitate quick tumor localization and to decrease operative time and blood transfusion requirements [3]. However, the disadvantages of dyes include peritonitis, infection, allergic reactions, and reabsorption within tissue planes [4]. In this report, we have described the use of fiducials as an alternative technique for this indication. The fiducials are inexpensive ($ 80 for five fiducials), easy to deploy, can be identified readily using fluoroscopy or intraoperative ultrasound, and (unlike dyes) do not extravasate into surrounding tissue.

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Competing interests: Dr Varadarajulu is a Consultant for Boston Scientific Corporation and Olympus Corporation.

• References

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