[333] Intra-Abdominal Neuroendocrine Tumor Diagnosed by Endoscopic Ultrasound-Guided Fine Needle Aspiration (EUS-FNA): A Retrospective Study from an Academic Tertiary Center

Roula Albadine, Genevieve Soucy, Anand V Sahai, Sarto C Paquin, Gilles Gariepy. Centre Hospitalier Universitaire de Montréal, Montréal, QC, Canada

Background: Neoplastic lesions of the pancreas, liver, retroperitoneal lymph nodes can be better visualized and appropriately sampled with fine-needle aspiration biopsy by endoscopic ultrasound (EUS-FNA). Diagnosis of pancreatic endocrine tumor can be rendered, in most cases, without difficulty based on cytomorphologic and immunophenotypic features. This study reviews the usefulness and accuracy of EUS-FNA in the diagnosis of neuroendocrine tumor (NET) in pancreas, liver, and lymph nodes.
Design: This is a retrospective study. Intra-abdominal EUS-FNA specimens (2003-2012) with a NET were retrieved. Metastatic small cell carcinoma was excluded. Immunohistochemistry study (small panel: CD57, CD56, synaptophysin, chromogranin A and B) was performed when cell block was available. Cases were classified as consistent with NET, possible/suggestive of NET, few cells with neuroendocrine differentiation. Clinicopathologic data were collected. On site cytopatholgic evaluation was done in all cases.
Results: We retrieved 148 patient specimens. Overall accuracy of EUS-FNA compared to definitive histopathology of surgical specimen was 85% (81/95). In 14 cases, there was little discrepancy. Final diagnosis was: Paragangliomas (3 cases); 1 intra pancreatic and 2 retroperitoneal; composite carcinoma with ductal, acinar, endocrine components (5 cases); Schwannoma (1 case); Metastasis from acinar cell carcinoma (1 case); Solid pseudopapillary tumor (3 cases); And 1 case with chronic pancreatitis. The definitive histopathology on surgical specimen was not available for 53 cases (surgery not indicated or patients scheduled for surgery).
Conclusions: Diagnosis of neuroendocrine tumor on EUS-FNA of intra-abdominal masses was rendered when cytomorphologic features were clear. Uncommon cytomorphologic features may impose a diagnostic challenge expending the differential diagnosis to include: acinar cell carcinoma, solid pseudopapillary tumor, composite carcinoma and metastatic neuroendocrine carcinoma. Distinction may have clinical implications. Correlation of cytomorphologic features and ancillary studies (a larger mmunohistochemistry panel when sufficient material is available) with the clinical and radiological information are essential to establish an accurate diagnosis.
Category: Cytopathology

Monday, March 4, 2013 1:00 PM

Poster Session II # 70, Monday Afternoon


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