Burcu Saka

POORLY DIFFERENTIATED NEUROENDOCRINE CARCINOMAS OF THE PANCREAS: A CLINICOPATHOLOGIC ANALYSIS OF 44 CASES

Background:In the pancreas, poorly differentiated neuroendocrine carcinomas include small cell carcinoma and large cell neuroendocrine carcinoma and are rare; data regarding their pathologic and clinical features are very limited. Design:A total of 107 pancreatic resections originally diagnosed as poorly differentiated neuroendocrine carcinomas were reassessed using the classification and grading (mitotic rate/Ki67 index) criteria put forth by the World Health Organization in 2010 for the gastroenteropancreatic system. Immunohistochemical labeling for neuroendocrine and acinar differentiation markers was performed. Sixty-three cases were reclassified, mostly as well-differentiated neuroendocrine tumor (NET) or acinar cell carcinoma, and eliminated. The clinicopathologic features and survival of the remaining 44 poorly differentiated neuroendocrine carcinomas were further assessed. Results:The mean patient age was 59 years (range, 21 to 82 y), and the male/female ratio was 1.4. Twenty-seven tumors were located in the head of the pancreas, 3 in the body, and 11 in the tail. The median tumor size was 4 cm (range, 2 to 18 cm). Twenty-seven tumors were large cell neuroendocrine carcinomas, and 17 were small cell carcinomas (mean mitotic rate, 37/10 and 51/10 HPF; mean Ki67 index, 66% and 75%, respectively). Eight tumors had combined components, mostly adenocarcinomas. In addition, 2 tumors had components of well-differentiated NET. Eighty-eight percent of the patients had nodal or distant metastatic disease at presentation, and an additional 7% developed metastases subsequently. Follow-up information was available for 43 patients; 33 died of disease, with a median survival of 11 months (range, 0 to 104 mo); 8 were alive with disease, with a median follow-up of 19.5 months (range, 0 to 71 mo). The 2- and 5-year survival rates were 22.5% and 16.1%, respectively. Conclusions:Poorly differentiated neuroendocrine carcinoma of the pancreas is a highly aggressive neoplasm, with frequent metastases and poor survival. Most patients die within less than a year. Most (61%) are large cell neuroendocrine carcinomas. Well-differentiated NET and acinar cell carcinoma are often misdiagnosed as poorly differentiated neuroendocrine carcinoma, emphasizing that diagnostic criteria need to be clearly followed to ensure accurate diagnosis.

Squamous cell and adenosquamous carcinomas of the gallbladder: clinicopathological analysis of 34 cases identified in 606 carcinomas

The information in the literature on squamous cell and adenosquamous carcinomas of the gallbladder is highly limited. In this study, 606 resected invasive gallbladder carcinoma cases were analyzed. Squamous differentiation was identified in 41 cases (7%). Those without any identifiable glandular-type invasive component were classified as pure squamous cell carcinomas (8 cases) and those with the squamous component constituting 25–99% of the tumors were classified as adenosquamous carcinomas (26 cases) and included into the analysis. The remaining 7 that had <25% squamous component were classified as adenocarcinoma with focal squamous change and excluded. The clinicopathological characteristics of adenosquamous carcinoma/squamous cell carcinomas were documented and contrasted with that of ordinary gallbladder adenocarcinomas. The average patient age was 65 years (range 26–81); female/male ratio, 3.8. In only 13%, there was a preoperative clinical suspicion of malignancy. Grossly, 58% presented as thickening and hardening of the wall and 6% were polypoid. In 12%, mucosa adjacent to the tumor revealed squamous metaplasia. All pure squamous cell carcinomas had prominent keratinization. Giant cells and tumor-infiltrating eosinophils were observed in 29 and 51% of the squamous cell carcinomas/adenosquamous carcinomas versus 10% (P=0.02) and 6% (P=0.001) in gallbladder adenocarcinomas, respectively. All but three cases had ‘advanced’ (pT2 and above) carcinomas. Follow-up was available in 31 patients: 25 died of disease (median=5 months, range 0–20), and 6 were alive (median=64 months, range 5–112.5). The survival of patients with squamous cell carcinomas/adenosquamous carcinomas was significantly worse than that of gallbladder adenocarcinomas (P=0.003), and this adverse prognosis persisted when compared with stage-matched advanced gallbladder adenocarcinoma cases (median=11.4 months, P=0.01). In conclusion, squamous differentiation was noted in 7% of gallbladder carcinomas. The incidence of adenosquamous carcinoma (defined as 25–99% of the tumor being squamous) was 4%, and that of pure squamous cell carcinoma (without any documented invasive glandular component) was 1%. Pure squamous cell carcinomas often showed prominent keratinization. The overall prognosis of adenosquamous carcinoma/squamous cell carcinoma appears to be even worse than that of ordinary adenocarcinomas. Most patients died within a few months; however, those few who were alive beyond 2 years in this cohort experienced long-term survival.

Calculation of the Ki67 index in pancreatic neuroendocrine tumors: a comparative analysis of four counting methodologies

Ki67 index is now an essential part of classification of pancreatic neuroendocrine tumors. However, its adaptation into daily practice has been fraught with challenges related to counting methodology. In this study, three reviewers used four counting methodologies to calculate Ki67 index in 68 well-differentiated pancreatic neuroendocrine tumors: (1) ‘eye-ball’ estimation, which has been advocated as reliable and is widely used; (2) automated counting by image analyzer; (3) manual eye-counting (eye under a microscope without a grid); and (4) manual count of camera-captured/printed image. Pearson’s correlation (R) was used to measure pair-wise correlation among three reviewers using all four methodologies. Average level of agreement was calculated using mean of R values. The results showed that: (1) ‘eye-balling’ was least expensive and fastest (average time <1 min) but had poor reliability and reproducibility. (2) Automated count was the most expensive and least practical with major impact on turnaround time (limited by machine and personnel accessibility), and, more importantly, had inaccuracies in overcounting unwanted material. (3) Manual eye count had no additional cost, averaged 6 min, but proved impractical and poorly reproducible. (4) Camera-captured/printed image was most reliable, had highest reproducibility, but took longer than ‘eye-balling’. In conclusion, based on its comparatively low cost/benefit ratio and reproducibility, camera-captured/printed image appears to be the most practical for calculating Ki67 index. Although automated counting is generally advertised as the gold standard for index calculation, in this study it was not as accurate or cost-effective as camera-captured/printed image and was highly operator-dependent. ‘Eye-balling’ produces highly inaccurate and unreliable results, and is not recommended for routine use.

Pronecrotic mixed lineage kinase domain-like protein expression is a prognostic biomarker in patients with early-stage resected pancreatic adenocarcinoma

Mixed lineage kinase domain‐like protein (MLKL) is a necrosome component mediating programmed necrosis that may be an important determinant of cancer cell death. The goal of the current study was to evaluate the prognostic value of MLKL expression in patients with pancreatic adenocarcinoma (PAC).

Molecular Genetics of Pancreatic Neoplasms and Their Morphologic Correlates An Update on Recent Advances and Potential Diagnostic Applications

OBJECTIVES To summarize the most clinically and biologically relevant advances in molecular/genetic characteristics of various pancreatic neoplasms, with morphologic correlation. METHODS Whole-exome sequencing of numerous benign and malignant pancreatic tumors, along with the plethora of highly sensitive molecular studies now available for analyzing these tumors, provide mounting evidence to support the long-held belief that cancer is essentially a genetic disease. These genetic discoveries have not only helped to confirm the age-old, morphology-based classifications of pancreatic neoplasia but have shed new light on their mechanisms. Many of these molecular discoveries are currently being used in preoperative diagnosis. RESULTS Mutations in KRAS, P16/CDKN2A, TP53, and SMAD4/DPC4 are commonly seen in ductal neoplasia but not in nonductal tumors; ductal adenocarcinomas with SMAD4/DPC4 loss are associated with widespread metastasis and poor prognosis. GNAS and RNF43 mutations have been discovered in most intraductal pancreatic mucinous neoplasms, providing critical molecular fingerprints for their diagnosis. Mutation in DAXX/ATRX is only seen in pancreatic neuroendocrine tumors, making it a useful potential marker in distinguishing these tumors from mimics. CONCLUSIONS When combined with morphologic observations, molecular studies will increase our understanding of the pathogenesis and morphomolecular signatures associated with specific neoplasms and provide new horizons for precision medicine and targeted therapies.

Having Pancreatic Cancer with Tumoral Loss of ATM and Normal TP53 Protein Expression Is Associated with a Poorer Prognosis

Purpose: To determine how often loss of ataxia-telangiectasia–mutated (ATM) protein expression occurs in primary pancreatic ductal adenocarcinomas and to determine its prognostic significance. Experimental Design: The expression of ATM and TP53 was determined by immunohistochemistry in 397 surgically resected pancreatic ductal adenocarcinomas (Hopkins; Johns Hopkins Medical Institutions, Baltimore, MD), a second set of 159 cases (Emory; Emory University Hospital, Atlanta, GA), and 21 cancers after neoadjuvant chemoradiotherapy. Expression was correlated with the clinicopathologic parameters, including survival. Results: Tumoral ATM loss was observed in one cancer known to have biallelic inactivation of ATM and 50 of the first 396 (12.8%) cases, significantly more often in patients with a family history of pancreatic cancer (12/49; 24.5%) than in those without (38/347; 11.0%; P = 0.019). In the Hopkins series, ATM loss was associated with a significantly decreased overall survival in patients whose cancers had normal TP53 expression (P = 0.019) and was a significant independent predictor of decreased overall survival (P = 0.014). Seventeen (10.7%) of 159 Emory cases had tumoral ATM loss and tumoral ATM loss/normal TP53 was associated with poorer overall survival (P = 0.1). Multivariate analysis of the combined Hopkins/Emory cases found that tumoral ATM loss/normal TP53 was an independent predictor of decreased overall survival [HR = 2.61; confidence interval (CI), 1.27–5.37; P = 0.009]. Of 21 cancers examined after neoadjuvant chemoradiotherapy, one had tumoral loss of ATM; it had no histologic evidence of tumor response. Conclusions: Tumoral loss of ATM protein was detected more often in patients with a family history of pancreatic cancer than in those without. Patients whose pancreatic cancers had loss of ATM but normal TP53 had worse overall survival after pancreatic resection. Clin Cancer Res; 20(7); 1865–72. ©2014 AACR.

Whipple Made Simple For Surgical Pathologists: Orientation, Dissection, and Sampling of Pancreaticoduodenectomy Specimens For a More Practical and Accurate Evaluation of Pancreatic, Distal Common Bile Duct, and Ampullary Tumors

Pancreaticoduodenectomy (PD) specimens present a challenge for surgical pathologists because of the relative rarity of these specimens, combined with the anatomic complexity. Here, we describe our experience on the orientation, dissection, and sampling of PD specimens for a more practical and accurate evaluation of pancreatic, distal common bile duct (CBD), and ampullary tumors. For orientation of PDs, identification of the “trapezoid,” created by the vascular bed at the center, the pancreatic neck margin on the left, and the uncinate margin on the right, is of outmost importance in finding all the pertinent margins of the specimen including the CBD, which is located at the upper right edge of this trapezoid. After orientation, all the margins can be sampled. We submit the uncinate margin entirely as a perpendicular inked margin because this adipose tissue–rich area often reveals subtle satellite carcinomas that are grossly invisible, and, with this approach, the number of R1 resections has doubled in our experience. Then, to ensure proper identification of all lymph nodes (LNs), we utilize the orange-peeling approach, in which the soft tissue surrounding the pancreatic head is shaved off in 7 arbitrarily defined regions, which also serve as shaved samples of the so-called “peripancreatic soft tissue” that defines pT3 in the current American Joint Committee on Cancer TNM. With this approach, our LN count increased from 6 to 14 and LN positivity rate from 50% to 73%. In addition, in 90% of pancreatic ductal adenocarcinomas there are grossly undetected microfoci of carcinoma. For determination of the primary site and the extent of the tumor, we believe bisectioning of the pancreatic head, instead of axial (transverse) slicing, is the most revealing approach. In addition, documentation of the findings in the duodenal surface of the ampulla is crucial for ampullary carcinomas and their recent site-specific categorization into 4 categories. Therefore, we probe both the CBD and the pancreatic duct from distal to the ampulla and cut the pancreatic head to the ampulla at a plane that goes through both ducts. Then, we sample the bisected pancreatic head depending on the findings of the case. For example, for proper staging of ampullary carcinomas, it is imperative to take the sections perpendicular to the duodenal serosa at the “groove” area, as ampullary carcinomas often extend to this region. Amputative (axial) sectioning of the ampulla, although good for documentation of the peri-Oddi spread of the intra-ampullary tumors, unfortunately disallows documentation of mucosal spread of the papilla of Vater tumors (those arising from the edge of the ampulla, where the ducts transition to duodenal mucosa and extending) into the neighboring duodenum. Axial sectioning also often fails to document tumor spread to the “groove” area. In conclusion, knowledge of the gross characteristics of the anatomic hallmarks is essential for proper dissection of PD specimens. The approach described above allows practical and accurate documentation and staging of pancreas, distal CBD, and ampullary cancers.

Intraductal tubulopapillary neoplasms of the bile ducts: clinicopathologic, immunohistochemical, and molecular analysis of 20 cases

Intraductal tubulopapillary neoplasm is a well-established entity in the pancreas. A similar, if not identical, tumor occurs also in the biliary tract. We conducted a multicenter study of 20 such lesions, focusing on their clinicopathologic characteristics and molecular profile. Biliary intraductal tubulopapillary neoplasms were seen in patients in their 60s (mean 62 years). The tumors were intrahepatic 70%, extrahepatic 10%, and perihilar 20%; mean tumor size was 6.9 cm. Histologically, all intraductal tubulopapillary neoplasms showed, in addition to their typical tubular pattern, solid areas (70%) or abortive papillae (50%). Necrosis was common (85%), predominantly focal (40%), and with ‘comedocarcinoma-like pattern’ in 40%. Immunohistochemically, these neoplasms were characterized by the expression of MUC1 (80%) and MUC6 (30%) and by the absence of MUC2 and MUC5AC. Associated invasive carcinomas were present in 16 (80%), mainly conventional tubular adenocarcinoma (50%). The molecular alterations observed included CDKN2A/p16 (intraductal components 44%, invasive 33%) and TP53 (intraductal components 17%, invasive 9%). Mutations in KRAS (intraductal 6%, invasive 0%), PIK3CA (intraductal 6%, invasive 0%), and loss of SMAD4/DPC4 (intraductal 7%, invasive 0%) were rare. No alterations/mutations were identified in IDH1/2, BRAF, GNAS, EGFR, HER2, and β-catenin. Follow-up information was available for 17 patients (85%) with mean follow-up 44 months. Overall combined survival rates showed favorable prognosis: 1 year 100%, 3 years 90%, and 5 years 90%. In conclusion, despite the relatively high incidence of invasive carcinoma (80%), available follow-up suggests that biliary intraductal tubulopapillary neoplasms have an indolent behavior. Molecular analyses highlight the low prevalence of alterations of common oncogenic signaling pathways in intraductal tubulopapillary neoplasm. Further studies using whole-exome sequencing are required to discover yet unknown molecular changes and to understand the carcinogenesis of intraductal tubulopapillary neoplasms.

KRAS mutant allele-specific imbalance is associated with worse prognosis in pancreatic cancer and progression to undifferentiated carcinoma of the pancreas.

KRAS codon 12 mutations are present in about 90% of ductal adenocarcinomas and in undifferentiated carcinomas of the pancreas. The role of KRAS copy number changes and resulting KRAS mutant allele-specific imbalance (MASI) in ductal adenocarcinoma (n=94), and its progression into undifferentiated carcinoma of the pancreas (n=25) was studied by direct sequencing and KRAS fluorescence in situ hybridization (FISH). Semi-quantitative evaluation of sequencing electropherograms showed KRAS MASI (ie, mutant allele peak higher than or equal to the wild-type allele peak) in 22 (18.4%) cases. KRAS FISH (performed on 45 cases) revealed a trend for more frequent KRAS amplification among cases with KRAS MASI (7/20, 35% vs 3/25, 12%, P=0.08). KRAS amplification by FISH was seen only in undifferentiated carcinomas (10/24, 42% vs 0/21 pancreatic ductal adenocarcinoma, 0%, P=0.0007). In 6 of 11 cases with both undifferentiated and well-differentiated components, transition to undifferentiated carcinoma was associated with an increase in KRAS copy number, due to amplification and/or chromosome 12 hyperploidy. Pancreatic carcinomas with KRAS MASI (compared to those without MASI) were predominantly undifferentiated (16/22, 73% vs 9/97, 9%, P<0.001), more likely to present at clinical stage IV (5/22, 23% vs 7/97, 7%, P=0.009), and were associated with shorter overall survival (9 months, 95% confidence interval, 5–13, vs 22 months, 95% confidence interval, 17–27; P=0.015) and shorter disease-free survival (5 months, 95% confidence interval, 2–8 vs 13 months, 95% confidence interval, 10–16; P=0.02). Our findings suggest that in a subset of ductal adenocarcinomas, KRAS MASI correlates with the progression to undifferentiated carcinoma of the pancreas.

Validation of histomolecular classification utilizing histological subtype, MUC1, and CDX2 for prognostication of resected ampullary adenocarcinoma

Background:Outcomes for ampullary adenocarcinomas are heterogeneous, and numerous methods of categorisation exist. A histomolecular phenotype based on histology, caudal-type homeodomain transcription factor 2 (CDX2) staining and Mucin 1 (MUC1) staining has recently been tested and validated in two cohorts. We attempt to validate this classification in a large patient population.Methods:Tissue samples from 163 patients with resected ampullary adenocarcinoma were classified based on histology and immunohistochemical expression of CDX2 and MUC1. A pancreaticobiliary histomolecular classification (PB) was defined as a sample with pancreaticobiliary histology, positive MUC1 and negative CDX2 expression.Results:There were 82 deaths; median follow-up of 32.4 months; and median overall survival of 87.7 (95% CI 42.9–109.5) months. PB comprised 28.2% of the cases. Factors associated with overall survival were histological subtype (P=0.0340); T1/2 vs T3/4 (P=0.001); perineural (P<0.0001) and lymphovascular (P=0.0203) invasion; and histomolecular intestinal histomolecular phenotype (INT) vs PB phenotype (106.4 vs 21.2 months, P<0.0001). Neither MUC1 nor CDX2 was statistically significant, although MUC1 positivity defined as ⩾10% staining was significant (P=0.0023). In multivariate analysis, age (HR 1.03), PB phenotype (HR 2.26) and perineural invasion (PNI; HR 2.26) were associated with poor survival.Conclusions:The prognostic ability of histomolecular phenotype has been validated in an independent cohort of ampullary adenocarcinoma patients.