Indeterminate diagnosis in fine-needle aspiration of the pancreas: reasons and clinical implications

Atypical cells in fine needle aspiration biopsies of pancreas: Causes, work-up, and recommendations for management

Endoscopic ultrasound-guided fine needle aspiration (EUS-FNA) is a sensitive and specific method for diagnosing cancer in solid pancreatic masses. However, some cases receive indeterminate atypical diagnoses, which creates management dilemmas. In the 2014 Papanicolaou Society of Cytopathology (PSC) standardized guidelines for pancreatobiliary cytology, specimens in the "Atypical" category show a spectrum of architectural and/or cellular changes beyond normal or reactive, but, quantitatively or qualitatively, insufficient for classification as neoplastic (benign/other), suspicious or positive for malignancy. Implementation of the PSC system decreased atypical diagnoses, particularly for cystic lesions, and redistributed many cases into benign and neoplastic categories. Because no set cytologic criteria exist for the "Atypical" category there is wide variability in its use, and its frequency ranges from 0%-16% (mean 6%). It consists of a heterogeneous mix of cases that occur because of preanalytic, lesion-specific (low cellularity, necrosis, cystic, reactive and premalignant changes), to pathologist-dependent factors (experience, expertise, training and institutional case volume). Outcomes of atypical diagnoses in solid pancreatic masses range from benign to premalignant and malignant and include reactive atypia in pancreatitis, well differentiated adenocarcinoma, and non-ductal malignancies. The associated risk of malignancy (ROM) ranges from 28%-100%, with an overall intermediate ROM in large-scale studies. Cytopathologists and institutions should monitor and keep their personal and/or laboratory's atypical rates low by judiciously using rapid onsite evaluation, ancillary studies, consensus or expert review, as well as correlation with clinical and radiologic findings. Early repeat EUS-FNA is indicated for unresolved cases.

Endoscopic ultrasound-fine needle biopsies of pancreatic lesions: Prospective study of histology quality using Franseen needle

BACKGROUND

The introduction of fine needle biopsies (FNB) to clinical practice presents a changing trend towards histology in the endoscopic ultrasound-guided tissue acquisition (EUS-TA).

AIM

To evaluate the clinical performance of a new FNB needle, the 22-gauge (22G) Franseen needle, when sampling pancreatic solid lesions.

METHODS

Consecutive patients with an indication for EUS-TA for the assessment of pancreatic solid lesions were included in this prospective, single-center, single-arm trial. Each patient underwent a puncture of the lesion two times using the 22G Franseen needle and the obtained samples were directly placed into formalin for histological analysis. The primary study endpoint was the rate of high-quality obtained specimen. Secondary endpoints included the length and diameter of the core specimen, the diagnostic accuracy and the complication rate.

RESULTS

From June 2017 to December 2018, forty patients with pancreatic solid lesions (22 females; mean age 67.2 years) were enrolled. Tissue acquisition was achieved in all cases. High-quality histology, rated with Payne score 3, was obtained in 37/40 cases (92.5%) after two needle passes. The mean size of the acquired histological core tissue was 1.54 mm × 0.39 mm. The diagnostic accuracy for the correct diagnosis was 85% (34/40). Only one adverse event was occurred, consisting of a self-limiting bleeding in the puncture site.

CONCLUSION

The 22G Franseen needle achieved according to our standardized protocol a high rate of histological core procurement, and a high diagnostic accuracy, with one minor adverse event reported.

Indeterminate diagnoses in EUS-guided FNA of the pancreas: analysis of cytologist and clinician perceptions, cytologic features, and clinical outcomes

INTRODUCTION

Indeterminate "atypical" or "suspicious for malignancy" diagnoses in the evaluation of pancreatic fine-needle aspiration (FNA) specimens can present challenges in the clinical management of patients with pancreatic masses. A main goal of this study was to identify, via survey, potential differences in perception between cytologists and clinicians with regard to the implications of, and factors contributing to, indeterminate diagnoses. We also evaluated clinical practice at our institution as it relates to such diagnoses and identified clinicopathologic features associated with indeterminate diagnoses, which allowed for correlation with survey results.

MATERIALS AND METHODS

Online surveys were sent to cytologists and clinicians to gather information on the respondents' experiences with pancreatic endoscopic ultrasound-guided FNA and their perceptions about the indeterminate diagnostic categories. Cytological specimens and patient medical records were reviewed to collect data on specimen acquisition, cytological features, tumor characteristics, and patient management.

RESULTS

Survey responses revealed that cytologists and clinicians held similar perceptions of the clinical impact of the indeterminate categories but had dissimilar ideas on the factors contributing to these diagnoses. Statistically significant associations were identified between indeterminate diagnoses and the following variables: number of passes performed; adequacy on rapid on-site evaluation; repeat FNA procedures; lesions with cystic changes; and well-differentiated tumor cytomorphology.

CONCLUSIONS

Awareness of the perceptions of cytologists and clinicians about, as well as the clinical features and cytologic variables associated with, "indeterminate" cases has the potential to improve patient care.

22-gauge core vs 22-gauge aspiration needle for endoscopic ultrasound-guided sampling of abdominal masses

AIM

To compare the aspiration needle (AN) and core biopsy needle (PC) in endoscopic ultrasound-guided fine needle aspiration (EUS-FNA) of abdominal masses.

METHODS

Consecutive patients referred for EUS-FNA were included in this prospective single-center trial. Each patient underwent a puncture of the lesion with both standard 22-gauge (G) AN (Echo Tip Ultra; Cook Medical, Bloomington, Indiana, United States) and the novel 22G PC (EchoTip ProCore; Cook Medical, Bloomington, Indiana, United States) in a randomized fashion; histology was attempted in the PC group only. The main study endpoint was the overall diagnostic accuracy, including the contribution of histology to the final diagnosis. Secondary outcome measures included material adequacy, number of needle passes, and complications.

RESULTS

Fifty six consecutive patients (29 men; mean age 68 years) with pancreatic lesions (n = 38), lymphadenopathy (n = 13), submucosal tumors (n = 4), or others lesions (n = 1) underwent EUS-FNA using both of the needles in a randomized order. AN and PC reached similar overall results for diagnostic accuracy (AN: 88.9 vs PC: 96.1, P = 0.25), specimen adequacy (AN: 96.4% vs PC: 91.1%, P = 0.38), mean number of passes (AN: 1.5 vs PC: 1.7, P = 0.14), mean cellularity score (AN: 1.7 vs PC: 1.1, P = 0.058), and complications (none). A diagnosis on the basis of histology was achieved in the PC group in 36 (64.3%) patients, and in 2 of those as the sole modality. In patients with available histology the mean cellularity score was higher for AN (AN: 1.7 vs PC: 1.0, P = 0.034); no other differences were of statistical significance.

CONCLUSION

Both needles achieved high overall diagnostic yields and similar performance characteristics for cytological diagnosis; histological analysis was only possible in 2/3 of cases with the new needle.

Endoscopic ultrasound-guided pancreatic fine-needle aspiration: potential pitfalls in one institution's experience of 1212 procedures

BACKGROUND

Endoscopic ultrasound-guided fine-needle aspiration (EUS-FNA) has emerged as the diagnostic modality of choice for mass lesions in the pancreas. The objective of the current study was to determine the accuracy and pitfalls of EUS-FNA in the diagnosis of pancreatic lesions in cases that involved follow-up surgical resection.

METHODS

Cases of EUS-FNA of pancreatic lesions performed from 2007 to mid-2012 for which subsequent surgical resection was performed were retrieved from the department's database. The accuracy of the cytologic diagnosis was assessed using the histological diagnosis as the gold standard. The sensitivity, specificity, positive predictive value, and negative predictive value were calculated. "Neoplastic," "suspicious," and "malignant" were classified as a positive cytologic diagnosis. In one calculation method, "atypical" was also included as a positive cytologic diagnosis whereas in another it was not considered to be a positive cytological result. The cases with a cytologic-histological discrepancy were reviewed to identify sources of errors.

RESULTS

A total of 1212 cases from 1104 patients (518 women and 586 men; age range, 18-94 years [average age, 63.5 years]) were identified. Cytologic diagnoses included 52 unsatisfactory, 224 benign, 129 atypical, 140 neoplasm, 35 suspicious, and 632 malignant diagnoses. Of these cases, 397 patients had histological follow-up information available. The sensitivity, specificity, positive predictive value, and negative predictive value were 83.2%, 85.9%, 95.9%, and 56.1%, respectively, with atypical cases excluded from the analysis. When atypical cases were included as a positive cytologic diagnosis, the sensitivity, specificity, positive predictive value, and negative predictive value were 86.7%, 67.9%, 90.7%, and 58.5%, respectively, and were 73.7%, 87.7%, 95.6%, and 48.0%, respectively, when atypical cases were included as a negative cytologic diagnosis. The major difficulty in EUS-FNA cytology was to differentiate pancreatic mucinous neoplasms from contaminants of gastric mucosa. Other pitfalls included differentiating mucinous neoplasm from extensive pancreatic intraepithelial neoplasia, and endocrine tumor from nesidioblastosis versus acinar cell carcinoma or intrapancreatic spleen.

CONCLUSIONS

EUS-FNA is a valuable tool for the diagnosis of pancreatic lesions, especially solid malignant tumors. Cytologic-radiological correlation is essential in differentiating pancreatic mucinous neoplasms from gastric mucosa, because the former usually are found to have characteristic features on imaging. Pathologists should be aware of the pitfalls in the cytologic diagnosis of pancreatic lesions that may significantly change the clinical management of the patients.

Fluorescence in situ hybridization and K-ras analyses improve diagnostic yield of endoscopic ultrasound-guided fine-needle aspiration of solid pancreatic masses

OBJECTIVES

Endoscopic ultrasound (EUS)-guided fine-needle aspiration (FNA) is the main diagnostic modality for pancreatic mass lesions. However, cytology is often indeterminate, leading to repeat FNAs and delay in care. Here, we evaluate whether combining routine cytology with fluorescence in situ hybridization (FISH) and K-ras/p53 analyses improves diagnostic yield of pancreatic EUS-FNA.

METHODS

Fifty EUS-FNAs of pancreatic masses in 46 patients were retrospectively analyzed. Mean follow-up was 68 months. Thirteen initial cytologic samples (26%) were benign, 23 malignant (46%), and 14 atypical (28%). We performed FISH for p16, p53, LPL, c-Myc, MALT1, topoisomerase 2/human epidermal growth factor receptor 2, and EGFR, as well as K-ras/p53 mutational analyses.

RESULTS

On final diagnosis, 11 (79%) of atypical FNAs were malignant, and 3 benign (21%). Fluorescence in situ hybridization was negative in all benign and all atypical samples with final benign diagnosis. Fluorescence in situ hybridization plus K-ras analysis correctly identified 60% of atypical FNAs with final malignant diagnosis. Combination of routine cytology with positive FISH and K-ras analyses yielded 87.9% sensitivity, 93.8% specificity, 96.7% positive predictive value, 78.9% negative predictive value, and 89.8% accuracy.

CONCLUSIONS

Combining routine cytology with FISH and K-ras analyses improves diagnostic yield of EUS-FNA of solid pancreatic masses. We propose to include these ancillary tests in the workup of atypical cytology from pancreatic EUS-FNA.

Cytology of the Pancreas: A Practical Review for Cytopathologists

Pancreatic cytopathology plays a critical role in the management of patients with cystic and solid pancreatic masses. The frequency of pancreatic fine-needle aspiration continues to increase and general surgical pathologists and cytopathologists need to be aware of the most commonly encountered entities as well as the pitfalls associated with gastrointestinal tract contaminants in endoscopic ultrasound-guided fine-needle aspiration. This article focuses on the most commonly encountered pancreatic lesions and the importance of correlation of cytologic features with clinical, radiologic, and ancillary studies for accurate diagnosis.

Blinded prospective comparison of the performance of 22-gauge and 25-gauge needles in endoscopic ultrasound-guided fine needle aspiration of the pancreas and peri-pancreatic lesions

BACKGROUND

Both 22- and 25-gauge needles are used for endoscopic ultrasound (EUS)-guided fine-needle aspiration (FNA) of lesions, yet limited data exist on whether either offers an advantage over the other in terms of specimen cellularity and quality.

AIM

The aim of this study was to compare sample quality for 22- and 25-gauge needles in EUS-guided FNA of pancreatic and peri-pancreatic lesions.

METHODS

Between October 2005 and June 2006, 12 patients with pancreatic or peripancreatic lesions underwent EUS-guided FNA with both 22- and 25-gauge Wilson-Cook Echotip needles. All procedures were performed with an Olympus linear echoendoscope by the same endoscopist to eliminate operator-dependent variability. Needle order was selected randomly, and two passes were made with each needle, consisting of ten uniform to-and-fro movements on each pass with 10-ml syringe suction. The specimens were immediately stained and independently reviewed by two cytopathologists, who were blinded to the needle used. Cellularity was graded as 0 to 6, with 6 being most cellular.

RESULTS

No statistically significant difference in cellularity was detected between the two needle size groups by cytologist 1 (mean difference, 0.04; 95% confidence interval [CI], -1.22 to 1.30; p = 0.94) or by cytologist 2 (mean difference, 0.2; 95% CI, -1.23 to 1.65; p = 0.76). When the data from both cytologists were combined, no significant difference in cellularity was detected between the two needle sizes (mean difference, 0.125; 95% CI, -1.22 to 1.47; p = 0.84). No significant difference in cellularity was detected between cytologists 1 and 2 (mean difference, 0.17; 95% CI, -0.15 to 0.48; p = 0.27). When the order in which needles were used was compared, no significant difference in cellularity was detected (p = 0.75). Three mechanical failures occurred with 25-gauge needles, but none occurred with 22-gauge needles. The visibility of the needles on EUS did not differ. Cytologic diagnoses were achieved in all cases: seven pancreatic adenocarcinomas, one pancreatic giant cell carcinoma, one pancreatic neuroendocrine tumor, one metastatic non-small cell carcinoma, one metastatic colon carcinoma, and one pancreatitis. There were no procedure-related complications.

CONCLUSIONS

Both FNA needles provided accurate diagnoses in all patients. There was no significant difference between the 22- and 25-gauge needle groups in the independent interpretation of two cytopathologists with respect to cellular yield and ability to render a diagnosis.