Evan B. Grossman

Pitfalls in avoiding operation for autoimmune pancreatitis

BACKGROUND Despite improved clinical characterization, autoimmune pancreatitis is often still diagnosed only after a major operative procedure. This study seeks to elucidate the circumstances that contribute to an inaccurate preoperative diagnosis. METHODS Two independent reviewers identified retrospectively an institutional cohort of 68 patients with adequate clinical data to support the diagnosis of autoimmune pancreatitis. Further data regarding presentation, diagnostic studies, and clinical course was abstracted from medical records. Comparative analyses were performed between those patients who underwent major operative procedures and those who did not. RESULTS Fifty-three patients underwent operative intervention as their initial treatment. Compared to the 15 patients avoiding operation, these patients were less likely to have diffuse pancreatic enlargement identified on pretreatment imaging (8% vs 80%) or to have pretreatment serum IgG4 level evaluations (11% vs 100%). Among the 21 patients in whom IgG4 levels were first checked postoperatively, only 12 had increases of at least twice the upper limit of normal. Pretreatment fine needle aspirates were interpreted incorrectly as definite or suspicious for adenocarcinoma in 12 patients, of whom 10 underwent operation. Clinically important postoperative disease recurrence was suspected or proven in 13 patients. CONCLUSION Pitfalls leading to major pancreatic resections in autoimmune pancreatitis include unnecessarily high thresholds for initiating serum IgG4 evaluation, false positive cytologic evaluations for malignancy, and failure to recognize non-classic initial presentations, or recurrence of disease. Better diagnostic strategies are needed, but awareness of these specific findings should help to decrease the number of patients undergoing operation for unrecognized autoimmune pancreatitis.

Abstract B33: Classification of pancreatic cysts in a minority population through cytokine profiling of cyst fluid fine-needle aspirate

Pancreatic cyst detection rate has increased due to the widespread use of cross-sectional imaging. Pancreatic cysts can be divided pathologically into pseudocysts, non-neoplastic cysts such as serous cystadenomas, and pancreatic cystic neoplasms. Malignant potential is seen in pancreatic cystic neoplasms, particularly mucinous cystic neoplasms and intraductal papillary mucinous neoplasms. Proper identification of mucinous cysts warrants either continual surveillance or evaluation for surgical resection to prevent potential development of pancreatic adenocarcinoma. Large urban medical centers, serving a predominantly minority population with an increased incidence of pancreatic cancer, require accurate and prompt diagnosis of malignant cysts. Currently, the standard cyst fluid analyses include CEA, amylase and cytology. In many cases these are of limited value and new biomarkers need to be defined to assist in accurate designation of cyst type. Previous studies have used proteomic analyses to improve cyst identification. One candidate set of protein markers are cytokines, which are involved in cell-mediated responses. A subset of cytokines has been implicated in the carcinogenic process. We hypothesized that the cytokine concentration in the pancreatic cyst fluid obtained via endoscopic ultrasound fine-needle aspiration will be differentially detected and could be used as an additional test to differentiate mucinous cystadenomas and cystadenocarcinomas from pseudocysts and serous cystoadenomas. The study protocol was designed to determine the pancreatic cyst fluid cytokine levels between mucinous and nonmucinous pancreatic cysts using a slide-based quantitative multiplex cytokine antibody array (Raybiotech, Norcross, GA). The cytokine array allowed for the quantitative detection of 20 cytokines with the parallel measurement of individual cytokine standard curves. Initial screening of 18 samples (8 mucinous, 10 nonmucinous) demonstrated differential detection of multiple cytokine targets, such as IL-1α and IL-5 that were statistically significant (P Citation Format: Rajesh Ramachandran, Larry Siu, Vadim Kurbatov, Evan Grossman, Frank Gress, Laura Martello. Classification of pancreatic cysts in a minority population through cytokine profiling of cyst fluid fine-needle aspirate. [abstract]. In: Proceedings of the AACR Special Conference on Pancreatic Cancer: Innovations in Research and Treatment; May 18-21, 2014; New Orleans, LA. Philadelphia (PA): AACR; Cancer Res 2015;75(13 Suppl):Abstract nr B33.