Use of a Novel Through-the-Needle Micro-forceps “TNMF” for Pancreatic Cyst Wall Sampling by Endoscopic Ultrasound (EUS)

Abstract

Introduction: Accurate diagnosis of pancreatic cystic lesions is essential for guiding further management. Our study was designed to determine the feasibility, safety and accuracy of a novel tissue acquisition device, Through-the-Needle Micro-Forceps “TNMF”, to perform EUS guided pancreatic cyst wall tissue sampling in patients referred for pancreatic cyst evaluation. Methods: Sixteen patients with pancreatic cysts who underwent EUS and fine needle aspirate (FNA) using 19-gauge core needle were included. Results of TNMF were compared with those of FNA-cytology and surgical pathology. Positive TNMF and FNA results were defined as “the ability to microscopically visualize tissue cores and define the cyst's lining epithelium”. Procedure details were recorded prospectively. Results: 16 patients underwent TNMF at the time of EUS-FNA (mean age 60.3 year, 10 F/6 M). The mean cyst size at EUS was 28.6 x 23.3 mm (+ 9.5). Technical success rate was 100%. Histologically adequate microbiopsy of cyst wall tissue was obtained in 11 out of 16 patients (79%). The most common finding was Intraductal Papillary Mucinous Neoplasm “IPMN” (6). Among all IPMN biopsies, the grade of dysplasia was low (2), intermediate (1), not defined (2) and no dysplasia (1). Four patients had fibro-vascular tissue lining consistent with pseudocyst. One patient had adenocarcinoma. Histologically adequate FNA-cytology was obtained in 9 of 16 patients (56 %). The most common finding was IPMN (4), adenocarcinoma (2), pseudocyst (2) and solid pseudopapillary neoplasm (1). When TNMF results were indeterminate (5), FNA was useful in establishing a diagnosis in 3 patients. When FNA results were indeterminate (7), TNMF was useful in establishing a diagnosis in 5 patients (table 1). Combination of TNMF and FNA-cytology was successful in obtaining a diagnosis in 14 patients (81%). Four patients underwent surgical resection {adenocarcinoma (2) and IPMN with dysplasia (2)}. TNMF biopsies showed concordant diagnoses in 3 of 4 patients and was indeterminate in a patient with adenocarcinoma. FNA showed concordant diagnosis in 3 of these 4 patients. No reported adverse events such as significant bleeding, infection, or pancreatitis was noted. Conclusion: TNMF is safe and feasible. The addition of cyst wall biopsy to FNA-cytology can help achieve high rates of accurate diagnoses in pancreatic cystic lesions. In our series, TNMF appears a useful adjunct to FNA cytology.Table: No Caption available.