W1957 Novel Changes in NF-κB Activity During Progression and Regression Phases of Hyperplasia: Role of ERK1/2 and p38

Abstract

Introduction: Pancreatic endocrine neoplasms (PENs) are rare lesions with an estimated frequency of 1 per 100,000. An accurate diagnosis of PEN depends on characteristic cytomorphologic criteria in combination with clinical and radiologic findings, including the use of Endoscopic ultrasonography-guided fine needle aspiration cytology (EUS-FNA). Aims: To evaluate the diagnostic reliability of for PENs at our institution and attempt to identify cytomorphologic features that predict aggressive clinical behavior. Methods: A total of 774 EUS-FNA pancreatic cases were retrieved from the files at KU Medical Center for the years 2002 to 2008. Of these, 34 cases (4%) were diagnosed as positive or suspicious for PEN's. The cytologic features used as diagnostic criteria included clusters of monotonous small uniform cells, singly dispersed or loosely cohesive plasmacytoid cells (on Diff-Quik stained smears), scant to moderate granular cytoplasm, and stripped nuclei in a granular background. Of these, thirteen cases (8 females) had surgical or clinical follow-up in our institution. Cytomorphologic features were correlated with the clinical behavior of each tumor. The cytomorphologic features evaluated included cellularity, nuclear pleomorphism, macronucleoli, mitotic activity and tumor diathesis. Results: Mean age of the patients in this cohort was 56 years (range: 9-79). Cytology samples obtained by EUS showed PEN in all 13 patients and were subsequently confirmed by surgical pathology in 10. The mean size of the PEN's was 3.1 cm (range: 0.5-8.3cm) and were distributed in the head (n=4), body (n=4), tail (n= 4), and neck (n=1) of the pancreas. Eight patients (62%) had the lesions resected with tumor free margins, 5 lesions were found to be unresectable2 secondary to invasion of portal vein (n=1) or superior mesenteric vein (n=1); 2 due to evidence of hepatic metastasis (these patients underwent palliative surgery); and 1 because of a coexisting locally advanced adenocarcinoma of unknown primary. In the surgically resected PEN's, 4 were benign (3 insulinomas, 1 PPoma), and 4 were malignant islet cell tumors. The presence of tumor diathesis and mitoses correlated with malignancy, however other features such as cellularity, nuclear pleomorphism, and macronucleoli did not. Conclusion: EUS-FNA is a reliable diagnostic tool for evaluating PEN's. Identification of mitoses and tumor diathesis in the smears may predict a more aggressive clinical behavior.