Definitive diagnosis of neuroendocrine tumors using fine-needle aspiration-puncture guided by endoscopic ultrasonography

BACKGROUND: The detection and diagnosis of neuroendocrine tumors (NETs) is challenging. Endoscopic ultrasonography (EUS) has a significant role in the detection of NETs suspected from clinical manifestations or imaging techniques, as well as in their precise localization and cytological confirmation using EUS-Fine-needle aspiration-puncture (FNA). OBJECTIVE: To assess the usefulness and precision of EUS-FNAP in the differential diagnosis and confirmation of NETs, in a retrospective review of our experience. PATIENTS AND METHODS: in a total of 55 patients with suspected NETs who underwent radial or sectorial EUS, 42 tumors were detected in 40 cases. EUS-FNA using a 22G needle was performed for 16 cases with suspected functional (hormonal disorders: 6 cases) and non-functional NETs (10 cases). Ki 67 or immunocytochemistry (ICC) testing was performed for all.There was confirmation in 9 cases (5 female and 4 male) with a mean age of 51 years (range: 41-81 years).All tumors were located in the pancreas except for one in the mediastinum and one in the rectum, with a mean size of 19 mm (range: 10-40 mm). RESULTS: There were no complications attributable to FNA. Sensitivity was 100% and both precision and PPV were 89%, as a false positive result suggested a diagnosis with NET during cytology that surgery finally revealed to be a pancreatic pseudopapillary solid tumor. CONCLUSIONS: EUS-FNA with a 22G needle for NETs has high sensitivity and PPV at cytological confirmation with few complications.