Review of the cytologic features of noninvasive ductal carcinomas of the pancreas: differences from invasive ductal carcinoma

Diagnostic features of low- and high-grade mucinous neoplasms in pancreatic cyst FNA cytology

BACKGROUND

Pancreatic cyst cytology evaluates for neoplastic mucin and epithelial grade. This study describes cytological features of low- and high-grade mucinous neoplasms (MNs) using gastrointestinal contaminants for comparison.

METHODS

Histologically confirmed pancreatic cystic neoplasms were reviewed by a panel of cytopathologists to identify which, among 26 selected cytologic features, correlate significantly with low- and high-grade MN. A test for greater than or equal to four of eight high-grade features (three-dimensional architecture, high nuclear:cytoplasmic ratio, moderate nuclear membrane abnormalities, loss of nuclear polarity, hyperchromasia, >4:1 nuclear size variation in one cluster, karyorrhexis, and necrosis) was assessed for identifying a high-grade neoplasms. Additional characteristics of the cohort such as cyst fluid carcinoembryonic antigen results, molecular testing, Papanicolaou Society of Cytopathology classification, and select high-risk clinical features are described.

RESULTS

Endoscopic ultrasound fine-needle aspirations from 134 MN and 17 serous cystadenomas containing gastrointestinal contaminants were included. The MN consisted of 112 (84%) intraductal papillary MNs (low-grade = 69, 62%; high-grade = 24, 21%; and invasive = 19, 17%) and mucinous cystic neoplasms (low-grade = 20, 90%; high-grade = 2, 10%). Half had greater than five clusters of epithelium for analysis. Compared with gastrointestinal contaminants, mucin from MN was thick and colloid-like (40% vs. 6%, p < .01), covered >20% of the smear area (32% vs. none, p < .01), and contained histiocytes (46% vs. 18%, p = .04). Greater than or equal to four of eight select high-grade features was present in 36% of high-grade MN with sensitivity 37% and 98% specificity.

CONCLUSION

Colloid-like features, >20% of smear, and histiocytes correlated with MN. Testing for greater than or equal to four high-grade features had low sensitivity and high specificity for high-grade MN.

Utility of intraoperative cytology of resection margins in biliary tract and pancreas tumors

BACKGROUND

Intraoperative diagnosis of resection margins in the biliary tract and pancreas tumors is important in deciding extent of resection; however, diagnosis based solely on frozen sections is sometimes difficult. Therefore, we investigated the usefulness of intraoperative cytology (IC) combined with frozen section (FS) histology. We present the results with a discussion of the value of this combination and its associated problems.

METHODS

We examined 80 bile duct resection margin specimens from 42 patients, and 34 pancreatic resection margin specimens from 29 patients, who underwent intraoperative diagnosis of resection margins during surgery for biliary tract or pancreatic tumors between October 2012 and January 2014. IC was performed on imprint specimens prepared from surfaces of margins being examined. The results were compared with FS and final histology of operative materials.

RESULTS

In IC, excluding cases with insufficient material, the results for bile duct margins; sensitivity was 96.7%, specificity 100% and accuracy 98.7%. The results for pancreatic margins; sensitivity was 100%, specificity 92.9%, and accuracy 93.3%. In FS, the results for bile duct margins; sensitivity was 96.8%, specificity 100%, and accuracy 98.8%. The results for pancreatic margins; sensitivity was 66.7%, specificity 100%, and accuracy 97.1%.

CONCLUSION

IC is quick, highly accurate and very easy to perform. This study even included a specimen for which only IC led to an accurate diagnosis. IC used in combination with FS can achieve intraoperative diagnosis with high overall accuracy.

Low interobserver agreement in cytology grading of mucinous pancreatic neoplasms

BACKGROUND

Identifying high-grade features in patients with pancreatic mucinous neoplasms (MNs) is important for patient management. The reproducibility of MN cytology grading has been evaluated to a limited extent. In the current study, the authors evaluated interobserver variability in grading MNs and the identification of neoplastic mucin in endoscopic ultrasound-guided fine-needle aspiration specimens.

METHODS

A 54-case grading set was created from histologically confirmed MNs (44 MNs) and nonmucinous lesions with abundant gastrointestinal contamination (10 nonmucinous lesions). Six observers received a tutorial, reviewed prescreened slides, and recorded: 1) a diagnosis according to a 6-tiered system (TS) (nondiagnostic, atypical [ATP], mucinous cyst low grade [MCLG], mucinous cyst high grade, suspicious for adenocarcinoma, and positive for adenocarcinoma); 2) the cyst fluid carcinoembryonic antigen diagnosis (CEADX); and 3) the presence of neoplastic musin. Interobserver agreement (IOA) was evaluated by calculation of kappa coefficients (Kappa). Diagnostic accuracy was not evaluated.

RESULTS

The IOA was lowest for the 6-TS (Kappa, 0.13; P<.001). The CEADX was available for 18 cases (33%), including 6 of 24 MCLG cases (25%). CEADX modestly improved IOA for combined tiers of the 6-TS with ATP and MCLG as separate categories. The highest IOA was noted with a 3-TS (nondiagnostic, ATP/MCLG, and mucinous cyst high grade/suspicious for adenocarcinoma/positive for adenocarcinoma [Kappa, 0.28; P<.001]) and various 4-TS (Kappa, 0.22-0.23). IOA was found to be low for neoplastic mucin (Kappa = 0.15; P<.001).

CONCLUSIONS

In a study using simulated cytology practice, observers demonstrated fair IOA for grading MNs and low IOA for identifying neoplastic mucin. Knowledge of the cyst fluid CEA level was found to modestly improve the IOA for low-grade lesions.

Dysplasia at the surgical margin is associated with recurrence after resection of non-invasive intraductal papillary mucinous neoplasms

BACKGROUND

The significance of a positive margin in resected non-invasive pancreatic intraductal papillary mucinous neoplasms (IPMN) remains controversial. The aim of this study was to determine recurrence rates when dysplasia was present at the final surgical margin.

METHODS

A prospectively maintained database identified 192 patients undergoing resection of non-invasive IPMN. Pathological, peri-operative and recurrence data were analysed.

RESULTS

Ductal dysplasia was identified at the final surgical margin in 86 patients (45%) and defined as IPMN or Pancreatic Intraepithelial Neoplasia PanIN in 38 (20%) and 54 (28%) patients, respectively. At a median follow-up of 46 months, 40 (21%) patients recurred with 31 developing radiographical evidence of new cysts, 6 re-resected for IPMN and 3 diagnosed with pancreatic cancer within the remnant. Of those with margin dysplasia, 31% developed recurrent disease compared with 13% in those without dysplasia (P = 0.002). On multivariate analysis, margin dysplasia was associated with a three-fold increased risk of recurrence (P = 0.02). No relationship between dysplasia and development of pancreatic cancer was found.

DISCUSSION

In this study, dysplasia at the margin after a pancreatectomy for non-invasive IPMN was associated with recurrence in the remnant gland, but not at the resection margin. While this finding may warrant closer follow-up, it does not identify a gland at higher risk for the subsequent development of invasive disease.

Cytopathology of the pancreas: neoplastic and nonneoplastic entities

Endoscopic ultrasound-directed fine-needle aspiration is a minimally invasive technique for the biopsy of pancreatic cysts and mass lesions. The technique is associated with low morbidity and high diagnostic accuracy. Interpretation of cytologic material obtained from the pancreas is complex because of the large number of reactive processes and benign and malignant neoplasms arising within the pancreas. The cytologic appearances of a majority of pancreatic neoplasms are characteristic, allowing precise recognition of the type of neoplasm present. Whereas separation of neuroendocrine, acinar, and ductal neoplasms is usually straightforward, the greatest diagnostic challenge in pancreatic fine-needle aspiration is the separation of atypical epithelium secondary to chronic pancreatitis from well-differentiated ductal adenocarcinoma. Recently, a number of in situ lesions have been identified, complicating the cytologic diagnosis of pancreatic neoplasia. These noninvasive lesions include pancreatic intraepithelial neoplasia and intraductal papillary mucinous neoplasm.

Distinct populations of metastases-enabling myeloid cells expand in the liver of mice harboring invasive and preinvasive intra-abdominal tumor

The liver is the most common site of adenocarcinoma metastases, even in patients who initially present with early disease. We postulated that immune-suppressive cells in the liver of tumor-bearing hosts inhibit anti-tumor T cells, thereby accelerating the growth of liver metastases. Using models of early preinvasive pancreatic neoplasia and advanced colorectal cancer, aims of this study were to determine immune phenotype, stimulus for recruitment, inhibitory effects, and tumor-enabling function of immune-suppressive cells in the liver of tumor-bearing hosts. We found that in mice with intra-abdominal malignancies, two distinct CD11b(+)Gr1(+) populations with divergent phenotypic and functional properties accumulate in the liver, becoming the dominant hepatic leukocytes. Their expansion is contingent on tumor expression of KC. These cells are distinct from CD11b(+)Gr1(+) populations in other tissues of tumor-bearing hosts in terms of cellular phenotype and cytokine and chemokine profile. Liver CD11b(+)Gr1(+) cells are highly suppressive of T cell activation, proliferation, and cytotoxicity and induce the development of Tregs. Moreover, liver myeloid-derived suppressor cells accelerate the development of hepatic metastases by inactivation of cytotoxic T cells. These findings may explain the propensity of patients with intra-abdominal cancers to develop liver metastases and suggest a promising target for experimental therapeutics.

Fine-needle aspiration of cystic pancreatic mucinous tumor: oncotic cell as an aiding diagnostic feature in paucicellular specimens

In juxtaposition with imaging studies, endoscopic ultrasound-guided fine-needle aspiration has gained popularity in the initial evaluation of pancreatic masses, especially cystic lesions of pancreas. Cystic pancreatic mucinous tumors include mucinous cystic neoplasm and intraductal papillary mucinous tumor, both of which have been known to have a low malignant potential and a high rate of association with invasive adenocarcinoma. As such, preoperative diagnosis is of great significance in guiding patient management. Although fine-needle aspiration cytological diagnosis of pancreatic tumor in cellular specimens has been well described, as with other cystic lesions, the yield of diagnostic cells from needle aspiration of cystic pancreatic mucinous tumors is typically low. Cytological diagnosis from these paucicellular specimens remains challenging. An additional compounding problem is the high frequency of gastrointestinal mucin and epithelial contamination. The diagnostic morphology and criteria in these paucicellular specimens have not been well addressed in the literature. The cytopathologists' ongoing efforts tend to improve the diagnostic accuracy. In this current study, oncotic cells, characterized by cytoplasmic swelling and karyolysis, were analyzed from 17 cases of cystic pancreatic mucinous tumor, of which the diagnosis was either confirmed by surgical resection or supported by cell block and/or increased CEA. Oncotic cells were found in variable amounts in almost all the cystic pancreatic mucinous tumors in this series. None of the five fine-needle aspirations intended for aspirations of hypoechoic nonlesional pancreas, which yielded either gastrointestinal tract material only or admixture of gastrointestinal and normal pancreatic components, was found to contain oncotic cells, evidencing the utility of oncotic cell as a surrogate morphologic marker in aiding the diagnosis of cystic pancreatic mucinous tumor as well as its differentiation from gastrointestinal contaminant, particularly in paucicellular specimens.