Utilization of ancillary studies in the cytologic diagnosis of biliary and pancreatic lesions: The papanicolaou society of cytopathology guidelines for pancreatobiliary cytology

Abstract

The Papanicolaou Society of Cytopathology has developed a set of guidelines for pancreatobiliary cytology including indications for endoscopic ultrasound-guided fine-needle aspiration, terminology and nomenclature of pancreatobiliary disease, ancillary testing, and post-biopsy management. All documents are based on the expertise of the authors, a review of the literature, discussions of the draft document at several national and international meetings, and synthesis of selected online comments of the draft document. This document presents the results of these discussions regarding the use of ancillary testing in the cytologic diagnosis of biliary and pancreatic lesions. Currently, fluorescence in situ hybridization (FISH) appears to be the most clinically relevant ancillary technique for cytology of bile duct strictures. The addition of FISH analysis to routine cytologic evaluation appears to yield the highest sensitivity without loss in specificity. Loss of immunohistochemical staining for the protein product of the SMAD4 gene and positive staining for mesothelin support a diagnosis of ductal adenocarcinoma. Immunohistochemical markers for endocrine and exocrine differentiation are sufficient for a diagnosis of endocrine and acinar tumors. Nuclear staining for beta-catenin supports a diagnosis of solid-pseudopapilary neoplasm. Cyst fluid analysis for amylase and carcinoembryonic antigen aids in the preoperative classification of pancreatic cysts. Many gene mutations (KRAS, GNAS, VHL, RNF43, and CTNNB1) may be of aid in the diagnosis of cystic neoplasms. Other ancillary techniques do not appear to improve diagnostic sensitivity sufficiently to justify their increased costs.

UroVysion Multi-Target Fluorescence in situ Hybridization Assay for the Detection of Malignant Bile Duct Brushing Specimens: A Comparison with Routine Cytology

“…Similar findings were observed in Asian populations in several small-cohort studies [16, 17]. In summary, UroVysion FISH appears to improve diagnostic sensitivity [4, 5, 13]. The sensitivity of routine cytology in the studies with corresponding FISH assays appears to be lower than that reported in studies with routine cytology alone (Table 4) [11].…”

“…The UroVysion FISH assay is considered as diagnostically useful, and is the preferred test to complement routine cytology to aid in the detection of malignant pancreatobiliary strictures by the Papanicolaou Society of Cytopathology [4]. However, the possibility of false-positive FISH results should always be considered, and may limit the utility of FISH in the diagnosis of malignancy in bile duct brushing specimens.…”

“…It also provides therapeutic value in the evaluation and management of patients with bile duct stricture. The bile duct brushing routine cytology has high specificity, but rather poor sensitivity and negative predictive value for the detection of malignancy [4, 5]. …”

Serous Cystadenoma of the Pancreas: Potentials and Pitfalls of a Preoperative Cytopathologic Diagnosis

“…SCAs are reported to express inhibin, calponin, and somatostatin receptors -all of which can be identified using immunohistochemical staining. Although a small number of studies have found that this improves the diagnostic accuracy of cytology for SCAs [19][20][21] , in this study an adequate cyst lining was only found in 10% of smears with SCAs. Furthermore, immunostaining needs cell block preparation which may or may not have adequate cellularity for further evaluation, suggesting the utility of immunohistochemistry may be limited.…”

EUS in Pancreatic Cysts

“…The "string sign," a marker of viscosity, is performed by placing fluid between the thumb and index finger and gently pulling apart. If the fluid stretches out to at least 3.5 mm, this is consistent with a mucinous cyst [61]. SCAs typically have thin, serosanguinous or frankly bloody fluid.…”