N-cadherin: A diagnostic marker to help discriminate primary liver carcinomas from extrahepatic carcinomas.

Distinguishing primary liver cancer (PLC), namely hepatocellular carcinoma (HCC) and intrahepatic cholangiocarcinoma (iCCA), from liver metastases is of crucial clinical importance. Histopathology remains the gold standard, but differential diagnosis may be challenging. While absent in most epithelial, the expression of the adherens junction glycoprotein N-cadherin is commonly restricted to neural and mesenchymal cells, or carcinoma cells that undergo the phenomenon of epithelial-to-mesenchymal transition (EMT). However, we recently established N- and E-cadherin expression as hallmarks of normal hepatocytes and cholangiocytes, which are also preserved in HCC and iCCA. Therefore, we hypothesized that E- and/or N-cadherin may distinguish between carcinoma derived from the liver vs carcinoma of other origins. We comprehensively evaluated E- and N-cadherin in 3359 different tumors in a multicenter study using immunohistochemistry and compared our results with previously published 882 cases of PLC, including 570 HCC and 312 iCCA. Most carcinomas showed strong positivity for E-cadherin. Strong N-cadherin positivity was present in HCC and iCCA. However, except for clear cell renal cell carcinoma (23.6% of cases) and thyroid cancer (29.2%), N-cadherin was only in some instances faintly expressed in adenocarcinomas of the gastrointestinal tract (0%-0.5%), lung (7.1%), pancreas (3.9%), gynecological organs (0%-7.4%), breast (2.2%) as well as in urothelial (9.4%) and squamous cell carcinoma (0%-5.6%). As expected, N-cadherin was detected in neuroendocrine tumors (25%-75%), malignant melanoma (46.2%) and malignant mesothelioma (41%). In conclusion, N-cadherin is a useful marker for the distinction of PLC vs liver metastases of extrahepatic carcinomas (P < .01).

Mixed Hepatocellular Cholangiocarcinoma: A Comparison of Survival between Mixed Tumors, Intrahepatic Cholangiocarcinoma and Hepatocellular Carcinoma from a Single Center.

BACKGROUND: Hepatocellular carcinoma (HCC) is the most frequent primary liver malignancy, followed by intrahepatic cholangiocarcinoma (ICC). In addition, there is a mixed form for which only limited data are available. The aim of this study was to compare recurrence and survival of the mixed form within the cohorts of patients with HCC and ICC from a single center. METHODS: Between January 2008 and December 2020, all patients who underwent surgical exploration for ICC, HCC, or mixed hepatocellular cholangiocarcinoma (mHC-CC) were included in this retrospective analysis. The data were analyzed, focusing on preoperative and operative details, histological outcome, and tumor recurrence, as well as overall and recurrence-free survival. RESULTS: A total of 673 surgical explorations were performed, resulting in 202 resections for ICC, 344 for HCC (225 non-cirrhotic HCC, ncHCC; 119 cirrhotic HCC, cHCC), and 14 for mHC-CC. In addition, six patients underwent orthotopic liver transplant (OLT) in the belief of dealing with HCC. In 107 patients, tumors were irresectable (resection rate of 84%). Except for the cHCC group, major or even extended liver resections were required. Vascular or visceral extensions were performed regularly. Overall survival (OS) was highly variable, with a median OS of 17.6 months for ICC, 26 months for mHC-CC, 31.8 months for cHCC, and 37.2 months for ncHCC. Tumor recurrence was common, with a rate of 45% for mHC-CC, 48.9% for ncHCC, 60.4% for ICC, and 67.2% for cHCC. The median recurrence-free survival was 7.3 months for ICC, 14.4 months for cHCC, 16 months for mHC-CC, and 17 months for ncHCC. The patients who underwent OLT for mHC-CC showed a median OS of 57.5 and RFS of 56.5 months. CONCLUSIONS: mHC-CC has a comparable course and outcome to ICC. The cholangiocarcinoma component seems to be the dominant one and, therefore, may be responsible for the prognosis. 'Accidental' liver transplant for mHC-CC within the Milan criteria offers a good long-term outcome. This might be an option in countries with no or minor organ shortage.

N-Cadherin Distinguishes Intrahepatic Cholangiocarcinoma from Liver Metastases of Ductal Adenocarcinoma of the Pancreas.

Carcinomas of the pancreatobiliary system confer an especially unfavorable prognosis. The differential diagnosis of intrahepatic cholangiocarcinoma (iCCA) and its subtypes versus liver metastasis of ductal adenocarcinoma of the pancreas (PDAC) is clinically important to allow the best possible therapy. We could previously show that E-cadherin and N-cadherin, transmembrane glycoproteins of adherens junctions, are characteristic features of hepatocytes and cholangiocytes. We therefore analyzed E-cadherin and N-cadherin in the embryonally related epithelia of the bile duct and pancreas, as well as in 312 iCCAs, 513 carcinomas of the extrahepatic bile ducts, 228 gallbladder carcinomas, 131 PDACs, and precursor lesions, with immunohistochemistry combined with image analysis, fluorescence microscopy, and immunoblots. In the physiological liver, N-cadherin colocalizes with E-cadherin in small intrahepatic bile ducts, whereas larger bile ducts and pancreatic ducts are positive for E-cadherin but contain decreasing amounts of N-cadherin. N-cadherin was highly expressed in most iCCAs, whereas in PDACs, N-cadherin was negative or only faintly expressed. E- and N-cadherin expression in tumors of the pancreaticobiliary tract recapitulate their expression in their normal tissue counterparts. N-cadherin is a helpful marker for the differential diagnosis between iCCA and PDAC, with a specificity of 96% and a sensitivity of 67% for small duct iCCAs and 50% for large duct iCCAs.

Integrative Analysis of Intrahepatic Cholangiocarcinoma Subtypes for Improved Patient Stratification: Clinical, Pathological, and Radiological Considerations.

Intrahepatic cholangiocarcinomas (iCCAs) may be subdivided into large and small duct types that differ in etiology, molecular alterations, therapy, and prognosis. Therefore, the optimal iCCA subtyping is crucial for the best possible patient outcome. In our study, we analyzed 148 small and 84 large duct iCCAs regarding their clinical, radiological, histological, and immunohistochemical features. Only 8% of small duct iCCAs, but 27% of large duct iCCAs, presented with initial jaundice. Ductal tumor growth pattern and biliary obstruction were significant radiological findings in 33% and 48% of large duct iCCAs, respectively. Biliary epithelial neoplasia and intraductal papillary neoplasms of the bile duct were detected exclusively in large duct type iCCAs. Other distinctive histological features were mucin formation and periductal-infiltrating growth pattern. Immunohistochemical staining against CK20, CA19-9, EMA, CD56, N-cadherin, and CRP could help distinguish between the subtypes. To summarize, correct subtyping of iCCA requires an interplay of several factors. While the diagnosis of a precursor lesion, evidence of mucin, or a periductal-infiltrating growth pattern indicates the diagnosis of a large duct type, in their absence, several other criteria of diagnosis need to be combined.

[Digital teaching in pathology: experiences from Mainz]. / Digitale Lehre in der Pathologie: Erfahrungen aus Mainz.

BACKGROUND: Due to the corona pandemic, digital teaching has become especially important in education and has led to a restructuring of teaching, not only in the subject of surgical pathology. OBJECTIVES: In this article, different forms of e­learning are presented and illustrated using the example of teaching surgical pathology and neuropathology at the University Medical Center Mainz. RESULTS: Before the onset of the corona pandemic in spring 2020, digitization had already assumed great importance for teaching in the technology- and method-oriented subject of surgical pathology. In particular, the possibility of virtual microscopy via scanned slides with a digital slide server has been used in many pathology institutes. Virtual microscopy often partially or completely replaced conventional microscopy of histologic slide collections. Complementary virtual learning offers are becoming more and more important. These include asynchronously provided lectures or macroscopy videos, video conferences, scripts and communication via learning platforms. In addition, electronic exams have become an indispensable part of teaching. Nevertheless, the corona pandemic revealed how important personal contact with students is to achieve optimal learning success; learning forms with a combination of face-to-face teaching and e­learning in the sense of blended learning are of particular importance. CONCLUSIONS: As part of blended learning, digital teaching is an ideal complement to face-to-face teaching and is changing teaching in the longer term, not only in the field of surgical pathology. Digital learning formats will remain in the future and will at least partially replace classroom formats such as lectures.

Liver Resection for Intrahepatic Cholangiocarcinoma-Single-Center Experience with 286 Patients Undergoing Surgical Exploration over a Thirteen Year Period.

BACKGROUND: Intrahepatic cholangiocarcinoma (iCCA) accounts for about 10% of primary liver cancer. Surgery is the only potentially curative treatment. We report on our current series of 229 consecutive hepatic resections for iCCA, which is one of the largest Western single-center series published so far. METHODS: Between January 2008 to December 2020, a total of 286 patients underwent 307 surgical explorations for intended liver resection of iCCA at our department. Data were analyzed with regard to (1) preoperative treatment of tumor, (2) operative details, (3) perioperative morbidity and mortality, (4) histopathology, (5) outcome measured by tumor recurrence, treatment of recurrence and survival and (6) prognostic factors for overall and disease-free survival. RESULTS: the resectability rate was 74.6% (229/307). In total, 202 primary liver resections, 21 repeated, 5 re-repeated, and 1 re-re-repeated liver resections were performed. In primary liver resections there were 77% (155/202) major hepatectomies. In 39/202 (20%) of patients additional hepatic wedge resections and in 87/202 (43%) patients additional 119 other surgical procedures were performed next to hepatectomy. Surgical radicality in first liver resections was 166 R0-, 33 R1- and 1 R2-resection. Following the first liver resection, the calculated 1-, 3- and 5-year-survival is 80%, 39%, and 22% with a median survival of 25.8 months. Until the completion of data acquisition, tumors recurred in 123/202 (60.9%) patients after a median of 7.5 months (range 1-87.2 months) after resection. A multivariate cox regression revealed tumor size (p < 0.001), T stage (p < 0.001) and N stage (p = 0.003) as independent predictors for overall survival. N stage (p = 0.040), preoperative therapy (p = 0.005), T stage (p = 0.004), tumor size (p = 0.002) and M stage (p = 0.001) were independent predictors for recurrence-free survival. CONCLUSIONS: For complete surgical removal, often extended liver resection in combination with complex vascular or biliary reconstruction is required. However, despite aggressive surgery, tumor recurrence is frequent and long-term oncological results are poor. This indicated that surgery alone is unlikely to make great strides in improving prognosis of patients with iCCA, instead clearly suggesting that liver resection should be incorporated in multimodal treatment concepts.

Clinicopathological Significance of Syndecan-1 in Cholangiocarcinoma: A Study Based on Immunohistochemistry and Public Sequencing Data.

BACKGROUND: Syndecan-1 (CD138; SDC1) is a heparan sulfate proteoglycan that has been attributed a key role in cancer progression in ductal adenocarcinoma of the pancreas. We therefore aimed to investigate the role of syndecan-1 in cholangiocarcinoma. METHODS: We analyzed syndecan-1 expression in a large, clinicopathologically well-characterized collective of 154 intrahepatic cholangiocarcinoma, 221 extrahepatic cholangiocarcinomas, and 95 gallbladder carcinomas as well as respective normal tissues and precursor lesions by immunohistochemistry with digital image analysis and correlated with recurrence-free survival and prognostic markers. Furthermore, we conducted an analysis of cancer genes in the cholangiocarcinoma cohort of The Cancer Genome Atlas (TCGA). RESULTS: During cholangiocarcinogenesis, syndecan-1-expression decreased when compared to normal bile ducts and biliary intraepithelial neoplasia; however, syndecan-1 levels were found to be elevated in lymph node metastases. In the TCGA cohort, high mRNA SDC1 levels were associated with poor prognosis in intrahepatic cholangiocarcinoma. However, in our large cohort, the immunohistochemical syndecan-1 expression did not significantly correlate with recurrence-free survival. CONCLUSIONS: Syndecan-1 was found to be downregulated during cholangiocarcinogenesis, yet we could not show significant effects on prognosis on protein level. Further analyses are needed to further depict its specific role.

SWI/SNF-deficient undifferentiated/rhabdoid carcinoma of the gallbladder carrying a POLE mutation in a 30-year-old woman: a case report.

BACKGROUND: Undifferentiated carcinoma of the biliary tract are highly aggressive malignancies. In other organs, a subgroup of undifferentiated carcinoma related to SWI/SNF complex-deficiency have been described. CASE PRESENTATION: A 30-year-old woman presented with rising inflammatory markers (C-reactive protein (CRP)). Ultrasound examination revealed a large tumor of the liver. A computed tomography scan was performed and was primarily interpreted as a tumor-forming liver abscess, possibly caused by gallbladder perforation. Subsequent liver segment resection was performed. Microscopic examination showed an undifferentiated carcinoma with rhabdoid morphology and prominent inflammatory infiltrate in the gallbladder base. With SWI/SNF immunohistochemistry, intact expression of SMARCB1, SMARCA4, ARID1A, but loss of SMARCA2 and PBRM1 was detected. Next-generation-sequencing detected KRAS, PBRM1 and ARID1B mutations, a deleterious splice-site mutation in the POLE-gene and a mutation in the TP53-gene. CONCLUSIONS: We were able to demonstrate loss of SMARCA2 expression and mutations characteristic of an SWI/SNF-deficient carcinoma in a tumor derived from the gallbladder. This is the first reported case of an undifferentiated carcinoma with rhabdoid features in the gallbladder carrying a POLE mutation and SWI/SNF-deficiency of PBRM1 and SMARCA2.

Influence of Lymphangio (L), Vascular (V), and Perineural (Pn) Invasion on Recurrence and Survival of Resected Intrahepatic Cholangiocarcinoma.

(1) Background: Intrahepatic cholangiocarcinoma (ICC) is a rare malignancy. Besides tumor, nodal, and metastatic status, the UICC TNM classification describes further parameters such as lymphangio- (L0/L1), vascular (V0/V1/V2), and perineural invasion (Pn0/Pn1). The aim of this study was to analyze the influence of these parameters on recurrence and survival. (2) Methods: All surgical explorations for patients with ICC between January 2008 and June 2018 were collected and further analyzed in our institutional database. Statistical analyses focused on perineural, lymphangio-, and vascular invasion examined histologically and their influence on tumor recurrence and survival. (3) Results: Of 210 patients who underwent surgical exploration, 150 underwent curative-intended resection. Perineural invasion was present in 41, lymphangioinvasion in 21, and vascular invasion in 37 patients (V1 n = 34, V2 n = 3). Presence of P1, V+ and L1 was significantly associated with positivity of each other of these factors (p < 0.001, each). None of the three parameters showed direct influence on tumor recurrence in general, but perineural invasion influenced extrahepatic recurrence significantly (p = 0.019). Whereas lymphangio and vascular invasion was neither associated with overall nor recurrence-free survival, perineural invasion was significantly associated with a poor 1-, 3- and 5-year overall survival (OS) of 80%, 35%, and 23% for Pn0 versus 75%, 23%, and 0% for Pn1 (p = 0.027). Concerning recurrence-free survival (RFS), Pn0 showed a 1-, 3- and 5-year RFS of 42%, 18%, and 16% versus 28%, 11%, and 0% for Pn1, but no significance was reached (p = 0.091). (4) Conclusions: Whereas lymphangio- and vascular invasion showed no significant influence in several analyses, the presence of perineural invasion was associated with a significantly higher risk of extrahepatic tumor recurrence and worse overall survival.

[Variation in morphology or two entities?] / Morphologische Variabilität oder zwei Entitäten?

A 37-year-old patient presented with B symptoms. On examination, hypodense liver lesions, multiple enlarged and partly confluent lymph nodes in the upper abdomen and retroperitoneum, as well as disseminated splenic and pulmonary foci were detected. Biopsies of a tumor in the coecum and the liver led to the diagnosis of an adenocarcinoma of the colon. In molecular pathology, microsatellite instability was detected. The post-neoadjuvant surgical specimen showed an unusual morphology and the question arose whether a second tumor should be considered.

Targeted next-generation sequencing of cancer genes in poorly differentiated thyroid cancer.

Poorly differentiated thyroid carcinoma (PDTC) is a rare malignancy with higher mortality than well-differentiated thyroid carcinoma. The histological diagnosis can be difficult as well as the therapy. Improved diagnosis and new targeted therapies require knowledge of DNA sequence changes in cancer-relevant genes. The TruSeq Amplicon Cancer Panel was used to screen cancer genomes from 25 PDTC patients for somatic single-nucleotide variants in 48 genes known to represent mutational hotspots. A total of 4490 variants were found in 23 tissue samples of PDTC. Ninety-eight percent (4392) of these variants did not meet the inclusion criteria, while 98 potentially pathogenic or pathogenic variants remained after filtering. These variants were distributed over 33 genes and were all present in a heterozygous state. Five tissue samples harboured not a single variant. Predominantly, variants in P53 (43% of tissue samples) were identified, while less frequently, variants in APC, ERBB4, FLT3, KIT, SMAD4 and BRAF (each in 17% of tissue samples) as well as ATM, EGFR and FBXW7 (each in 13% of tissue samples) were observed. This study identified new potential genetic targets for further research in PDTC. Of particular interest are four observed ERBB4 (alias HER4) variants, which have not been connected to this type of thyroid carcinoma so far. In addition, APC and SMAD4 mutations have not been reported in this subtype of cancer either. In contrast to other reports, we did not find CTNNB1 variants.