Improving diagnostic yield of pancreatic serous cystadenoma with cyst fluid ancillary testing, adjunct immunohistochemistry, and additional fine-needle biopsy sampling

BACKGROUND

Fine-needle aspiration (FNA) diagnosis of pancreatic serous cystadenoma (SCA) remains challenging. This retrospective study aimed to evaluate the roles of cyst fluid ancillary testing and combined fine-needle biopsy (FNB) in improving the diagnostic yield.

METHODS

The authors retrospectively reviewed cytology cases that were histologically confirmed SCAs. Clinical features and FNA cyst fluid biochemical and molecular analysis results along FNB findings were reviewed.

RESULTS

The study cohort included 31 cases from 13 male and 18 female patients with a mean age of 65. The original cytologic diagnoses were nondiagnostic (n = 6, 19%), negative for malignant cells/cyst contents (n = 7, 23%), atypical cells (n = 3, 10%), nonmucinous cyst (n = 11, 35%), and serous cystadenoma (n = 4, 13%). Cyst fluid carcinoembryonic antigen (CEA) analysis was performed in 17 cases, all of which showed a low CEA level (<192 ng/mL). All 14 cases with molecular testing showed a wild-type KRAS. Inhibin immunohistochemistry was retrospectively performed on the FNA cell blocks, inhibin was positive in six of seven cases tested. In 15 cases with concurrent FNA and FNB biopsies, the diagnosis of SCA was seen in only one FNA case (7%) but 13 FNB cases (87%).

CONCLUSIONS

This study suggests that FNA diagnosis of SCA remains challenging even with ancillary testing including cyst fluid CEA level and KRAS mutation analysis. Adjunct inhibin immunostaining may help improve the cytologic diagnosis of selective SCA cases. FNB appears superior to FNA for a definite diagnosis of SCA.

Intraductal papillary neoplasm of the bile duct: Cytomorphologic and molecular features

BACKGROUND

Intraductal papillary neoplasm of the bile duct (IPNB) is a rare premalignant neoplasm that can progress to invasive adenocarcinoma. In this retrospective study, cases of IPNB were reviewed to examine cytomorphologic and molecular features.

METHODS

IPNB cytology cases with histopathologic confirmation were retrieved from the pathology archives. The cytomorphologic features such as cellularity, architecture, cell type, and cellular details were analyzed.

RESULTS

The cohort included 13 cases (six brushings, six fine-needle aspirations [FNA], and one combined brushing and FNA). The lesions involved common bile duct in nine cases (69%) and hepatic duct in four cases (31%). Original cytological diagnoses included adenocarcinoma (five, 38%), suspicious for adenocarcinoma (one, 8%), neoplasm (three, 23%), atypical (three, 23%), and reactive (one, 8%). The cytomorphologic features included moderate/high cellularity (12, 92%), papillary and/or complex papillary architecture (10, 77%), columnar cells (11, 85%), vacuolated cytoplasm (12, 92%), enlarged nuclei (13, 100%), and fine granular chromatin (12, 92%). Background mucin, necrosis and acute inflammation were seen in four (31%), four (31%), and two (15%) cases, respectively. KRAS testing was performed in nine cases with mutant KRAS found in five (56%).

CONCLUSIONS

Our study demonstrated that IPNB cytology specimens were relatively cellular with a wide spectrum of cytomorphology; however, most cases harbored adenocarcinoma or high-grade dysplasia. The characteristic cytomorphologic features included papillary/complex papillary clusters of columnar cells with vacuolated cytoplasm, enlarged nuclei, and fine granular chromatin in relatively cellular specimens. KRAS mutations identified may have potential diagnostic and therapeutic implications.

Significance of KRAS mutation testing in biliary brushing cytology specimens: A 10-year retrospective review

BACKGROUND

Biliary strictures can be caused by benign and malignant conditions. A biliary duct brushing diagnosis can be challenging because of low cellularity and overlapping morphology among different entities, leading to a variable reported sensitivity. This study aimed to assess the value of KRAS mutation testing in adding cytological diagnosis of biliary duct brushings.

METHODS

With institutional review board approval, biliary duct brushing cytology specimens were collected from 269 patients with extrahepatic biliary stenosis between August 2011 and July 2021. The results of cytology and KRAS mutational analyses were evaluated in view of corresponding cytology examination and histopathological/clinical follow-up.

RESULTS

KRAS mutations were identified in 50 of 269 biliary stricture brushing cases (19%). Among the cases with available follow-up, 72% (34 of 47) of biliary brushings had confirmed malignancy when there were KRAS mutations. The overall specificity and sensitivity of KRAS mutation testing was 92% and 36%, respectively. KRAS mutation was significantly more enriched in pancreatic duct adenocarcinoma than in cholangiocarcinoma (66% vs 5%, P < .001). The absolute risk of malignancy was 3%, 28%, and 71%, respectively, in negative, atypical, and suspicious cytological diagnostic categories and the risks increased to 14%, 68%, and 95% in corresponding categories with KRAS mutation.

CONCLUSIONS

Our results suggested that KRAS mutational analysis can be considered supplementary to cytology diagnosis of biliary duct brushing for patients with extrahepatic biliary stenosis in clinical practice.

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-guided fine-needle aspiration biopsy of autoimmune pancreatitis: diagnostic clues and pitfalls

INTRODUCTION

Autoimmune pancreatitis (AIP) is an inflammatory process that has characteristic clinical, radiographic, and pathologic features but may mimic pancreatic malignancy. In this study, we reviewed our experience in the endoscopic ultrasound-guided fine-needle aspiration evaluation of pancreatic lesions in patients with AIP.

MATERIALS AND METHODS

We searched the cytopathology archives and identified a total of 6 cases that had endoscopic ultrasound-guided fine-needle aspiration evaluation and subsequent tissue biopsy or resection with a diagnosis of AIP. The clinical, cytologic, and histopathologic features were reviewed.

RESULTS

The original cytologic diagnoses included negative, atypical, and suspicious for malignancy in 2 cases each. On retrospective review, these cases were characterized cytologically by the presence of mixed epithelial cells, mixed lymphocytes, and plasma cells, as well as cellular stromal fragments. Cytologic atypia of epithelial cells was observed in 4 of 6 cases, including mild (3 cases) and moderate (1 case) atypia. KRAS mutation analysis was performed in 4 cases with an indeterminate cytology diagnosis, which was negative in all cases.

CONCLUSIONS

Our results demonstrate that the presence of trilineage epithelial, lymphoplasmacytic, and stromal elements may be suggestive but not definitive for a diagnosis of AIP. The role of KRAS mutation analysis in AIP remains inconclusive and may warrant further evaluation.

KRAS mutation testing in clinical practice

Activating mutation of KRAS plays a significant role in the pathogenesis of common human malignancies and molecular testing of KRAS mutation has emerged as an essential biomarker in the current practice of clinical oncology. The presence of KRAS mutation is generally associated with clinical aggressiveness of the cancer and reduced survival of the patient. Therapeutically, KRAS mutation testing has maximum utility in stratifying metastatic colorectal carcinoma and lung cancer patients for treatment with targeted therapy. Diagnostically, KRAS mutation testing is useful in the workup of pancreaticobiliary and thyroid cancers, particularly using cytological specimens. In the era of precision medicine, the role of KRAS mutation testing is poised to expand, likely in a setting of combinatorial therapeutic strategy and requiring additional mutation testing of its upstream and/or downstream effectors.

Trans-organ versus trans-mesenteric computed tomography-guided percutaneous fine-needle aspiration biopsy of pancreatic masses: feasibility and safety

AIM

To evaluate the safety and efficacy of computed tomography (CT)-guided percutaneous fine-needle aspiration biopsy (FNAB) of pancreatic masses that traverses the gastrointestinal tract or solid viscera.

MATERIALS AND METHODS

From January 2002 to December 2012, 144 patients underwent 165 CT-guided biopsies of pancreatic masses. Biopsies were performed using a 21 or 22 G needle. Cytology reports, medical records, and procedure details for all patients were retrospectively reviewed to evaluate the biopsy route, complications, and diagnostic accuracy.

RESULTS

Trans-organ biopsies of pancreatic masses were safely performed via a direct pathway traversing the stomach (n = 45), colon (n = 14), jejunum (n = 4), or liver (n = 5). There were five self-limiting mesenteric haematomas along the biopsy route on immediate post-procedure CT and all patients remained asymptomatic. All haematomas occurred after a trans-mesenteric approach rather than passage through abdominal organs. Three patients had acute pancreatitis. There was no significant difference in complications and diagnostic yields between the groups. The sensitivity, specificity, positive predictive value, and negative predictive value of final FNAB cytology for malignancy were 98.3%, 100%, 100% and 71.4%, respectively. The overall accuracy was 98.4%.

CONCLUSION

Percutaneous FNAB using the trans-organ approach is a safe and effective technique to diagnose pancreatic malignancy.