Pathology and genetics of pancreatic neoplasms with acinar differentiation

Diagnostic Pearls and Pitfalls in the Evaluation of Biopsies of the Pancreas

CONTEXT.—

The examination of small pancreatic biopsies is a difficult task for pathologists. This is due to the scant and fragmented material often obtained from diagnostic procedures as well as the significant overlap between different neoplastic and nonneoplastic entities. In the upcoming neoadjuvant era, biopsies could become even more important, representing the only possibility to look at the real histomorphology of tumors before chemotherapy-induced modifications.

OBJECTIVES.—

To summarize and discuss the state-of-the-art diagnostic workflow for small pancreatic biopsies, including the most important morphologic and immunohistochemical features and molecular alterations. The main diagnostic pearls and pitfalls of this challenging scenario are also discussed. The most important topics of this review are represented by: (1) pancreatic ductal adenocarcinoma, along with its main differential diagnoses, including autoimmune pancreatitis; (2) solid hypercellular neoplasms, including neuroendocrine neoplasms, acinar cell carcinoma, pancreatoblastoma, and solid pseudopapillary neoplasms; and (3) cystic lesions. Real-world considerations will also be presented and discussed.

DATA SOURCES.—

Sources included a literature review of published studies and the author's own work.

CONCLUSIONS.—

The correct diagnosis of pancreatic lesions is a crucial step in the therapeutic journey of patients. It should be based on robust, standardized, and reliable hallmarks. As presented and discussed here, the integration of morphology with immunohistochemistry, and, in selected cases, with molecular analysis, represents a decisive step in this complex scenario.

The response of pancreatic acinar cell carcinoma to platinum and olaparib therapy in a germline BRCA2 variant carrier: case report and literature review

A 73-year-old Japanese man with a history of distal biliary cancer treated by pancreatoduodenectomy developed pancreatic acinar cell carcinoma (PACC) treated by remnant pancreatectomy and adjuvant chemotherapy. Thirteen months after surgery, multiple liver metastases developed and FOLFOX chemotherapy was initiated. Based on the PACC diagnosis and a positive family history for breast and ovarian cancer genetic testing was performed which revealed a pathogenic germline BRCA2 variant (c.8629G > T, p.Glu2877Ter). Olaparib therapy was initiated and the metastases responded well (partial response). PACC is a BRCA2-associated cancer which may respond well to PARP inhibitors.

Acinar cell pancreatic carcinoma: a rare case of pancreatic tumor and short review of literature

Pancreatic acinar cell carcinoma (PACC) is a rare subgenre of pancreatic adenocarcinoma, where the cells show acinar architecture. Specified causes of this neoplasia have not yet been deduced and it usually appears with nonspecific symptoms. Diagnosis is based on its characteristics in various imaging techniques, on its histological characteristics and the expression of specific immunohistochemical biomarkers. Surgical excision of the tumor is usually performed with high chances of recurrence, whereas the benefits of radiotherapy and chemotherapy are still ambiguous. In this paper, a 51-year-old female patient with a mass in the head of the pancreas was taken as a case study. She presented with icterus and imaging showed a defined mass in the head of the pancreas accompanied by dilation of the biliary tree. Biopsy and histological assessment done after the surgical excision showed components of PACC differentiation. The patient was regulated after surgery, especially regarding endocrinology and immunology.

Treatment characteristics and outcomes of pure Acinar cell carcinoma of the pancreas - A multicentric European study on radically resected patients

BACKGROUND

Acinar cell carcinomas (ACC) belong to the exocrine pancreatic malignancies. Due to their rarity, there is no consensus regarding treatment strategies for resectable ACC.

METHODS

This is a retrospective multicentric study of radically resected pure pancreatic ACC. Primary endpoints were overall survival (OS) and disease-free survival (DFS). Further endpoints were oncologic outcomes related to tumor stage and therapeutic protocols.

RESULTS

59 patients (44 men) with a median age of 64 years were included. The median tumor size was 45.0 mm. 61.0% were pT3 (n = 36), nodal positivity rate was 37.3% (n = 22), and synchronous distant metastases were present in 10.1% of the patients (n = 6). 5-Years OS was 60.9% and median DFS 30 months. 24 out of 31 recurred systemically (n = 18 only systemic, n = 6 local and systemic). Regarding TNM-staging, only the N2-stage negatively influenced OS and DFS (p = 0.004, p = 0.001). Adjuvant treatment protocols (performed in 62.7%) did neither improve OS (p = 0.542) nor DFS (p = 0.159). In 9 cases, radical resection was achieved following neoadjuvant therapy.

DISCUSSION

Radical surgery is currently the mainstay for resectable ACC, even for limited metastatic disease. Novel (neo)adjuvant treatment strategies are needed, since current systemic therapies do not result in a clear survival benefit in the perioperative setting.

Rare ROS1-CENPW gene in pancreatic acinar cell carcinoma and the effect of crizotinib plus AG chemotherapy: A case report

BACKGROUND

This is the first report of an ROS1-CENPW fusion gene in pancreatic malignancies.

CASE SUMMARY

A 77-year-old woman with a pancreatic tumor and multiple liver metastases was admitted to our hospital. Genetic testing revealed the presence of the ROS1-CENPW fusion gene, a rare fusion gene that has not been previously reported in the field of pancreatic cancer. The patient received crizotinib plus AG (albumin paclitaxel plus gemcitabine) chemotherapy. After treatment, the patient's condition stabilized, and her prognosis was good.

CONCLUSION

The ROS1-CENPW gene treatment regimen used in this case is an excellent treatment option that provides new hope for patients with advanced pancreatic cancer and similar genetic mutations. To date, owing to the rarity of the ROS1-CENPW fusion gene, our team has encountered only a single case. Therefore, the efficacy of crizotinib plus AG chemotherapy in patients with pancreatic acinar cell carcinoma harboring the ROS1-CENPW fusion gene requires further validation.

Pancreatoblastoma in Elderly Adults: Report of Two Patients

Introduction. Pancreatoblastoma is a rare malignant epithelial neoplasm of the pancreas, which often shows multiple lines of differentiation, but is defined by neoplastic cells with acinar differentiation and characteristic squamoid nests. Pediatric patients are most commonly affected, and although a subset is known to occur in adults, the diagnosis is rarely considered in elderly adults. Methods. The clinicopathologic features of two cases of pancreatoblastoma in elderly patients were examined. Results. Two patients (age 80 and 81 years) presented with pancreatoblastoma, including one with early-stage pancreatic disease and one with liver metastasis. Biopsies and one pancreatic resection specimen showed characteristic histomorphologic features, including prominent acinar differentiation and abundant squamoid nests. Both cases had complete loss of SMAD4 (DPC4) immunolabeling. Next generation sequencing was performed on one case and revealed copy number loss of chromosome 11p and 9p21 (CDKN2A/B) and pathogenic or likely pathogenic variants in APC, SMAD4, and PIK3CA. The APC and SMAD4 variants occurred at allele frequencies suggestive of germline mutations, raising the possibility that this patient may have an inherited cancer predisposition syndrome. Conclusions. We present two cases which extend the upper age limit for reported pancreatoblastoma, including one with genetic findings suggestive of an inherited cancer predisposition syndrome.

Metachronous metastatic pancreatoblastoma to the liver in an elderly patient misdiagnosed as pancreatic acinar cell carcinoma

A woman in her 80s was evaluated for a liver mass. She had a history of what was reported as pancreatic acinar cell carcinoma resected with a pancreatoduodenectomy 10 years prior at another institution. Liver biopsy showed metastatic pancreatoblastoma (PB) and staging imaging showed no evidence of additional metastatic disease. She underwent laparoscopic non-anatomic partial hepatectomy and recovered uneventfully. The liver pathology was reviewed along with slides from her initial pancreatoduodenectomy, and both were noted to be consistent with PB. PB contains similar histological characteristics to pancreatic acinar cell carcinoma. Distinguishing between the two diagnoses is critical for accurately defining the prevalence, clinical course and prognosis associated with PB.

Adult Pancreatoblastoma: Report of 3 new Cases With Genetic Diversity and Autopsy Findings

We report the histopathological, immunohistochemical (IHC), and molecular findings in 3 patients with adult pancreatoblastoma, including 2 with autopsy features. The tumors were located in the tail and body of the pancreas, and the 2 autopsy examinations revealed liver and lung metastases. Histopathologically the neoplasms were composed of solid epithelial elements with nested or trabecular growth patterns, fibrous stroma, and squamoid clusters. Keratin 19 was positive mainly in squamoid corpuscles, and trypsin or chymotrypsin was positive in the acinar component. Neuroendocrine differentiation was observed in all tumors, and nuclear β-catenin expression in 2 tumors. Despite nuclear β-catenin expression, CTNNB1 mutation was found only in tumor 2. APC mutation was detected in tumor 1, and SMAD4 as well as MEN1 mutations in tumor 3. This last tumor also revealed chromosomal instability with many chromosomal losses and gains. The follow-up showed regional or distant metastases in all patients. Two patients died of disease after 3 and 26 months of follow-up and 1 patient is alive with no evidence of disease 6 years and 2 months after surgery. Adult pancreatoblastoma can display genetic heterogeneity, diverse histological appearance, and overlapping IHC findings. As a result, the differential diagnosis with other adult pancreatic tumors, such as acinar cell carcinoma, neuroendocrine neoplasm, solid pseudopapillary neoplasm, and mixed tumors may be challenging, especially when dealing with limited tumor tissue. The identification of squamoid corpuscles is essential for diagnosis. Although molecular findings might provide useful information, the integration of clinical, radiological, and histopathological findings is essential in pancreatoblastoma diagnosis.

Prolonged response on olaparib maintenance in metastatic pancreatic acinar cell carcinoma associated with a germline BRCA 2 mutation, revealed by severe panniculitis

This 38-year-old man has a familial BRCA2 mutation. He presented with skin erythema, polyarthritis, dactylitis, and febrile erythema nodosum; a biopsy of a liver metastase revealed acinar cell carcinoma of the pancreas. After FOLFIRINOX, olaparib was initiated, and 24 months after, the patient was PS 0 and asymptomatic.

Pancreatoblastomas and mixed and pure acinar cell carcinomas share epigenetic signatures distinct from other neoplasms of the pancreas

Pancreatic neoplasms are heterogenous and have traditionally been classified by assessing their lines of cellular differentiation using histopathologic methods, particularly morphologic and immunohistochemical evaluation. These methods frequently identify overlapping differentiation along ductal, acinar, and neuroendocrine lines, raising diagnostic challenges as well as questions regarding the relationship of these neoplasms. Neoplasms with acinar differentiation, in particular, frequently show more than one line of differentiation based on immunolabeling. Genome methylation signatures, in contrast, are better conserved within cellular lineages, and are increasingly used to support the classification of neoplasms. We characterized the epigenetic relationships between pancreatoblastomas, acinar cell carcinomas (including mixed variants), pancreatic neuroendocrine tumors, solid pseudopapillary neoplasms, and pancreatic ductal adenocarcinomas using a genome-wide array platform. Using unsupervised learning approaches, pancreatic neuroendocrine tumors, solid pseudopapillary neoplasms, ductal adenocarcinomas, and normal pancreatic tissue samples all localized to distinct clusters based on their methylation profiles, whereas all neoplasms with acinar differentiation occupied a broad overlapping region located between the predominantly acinar normal pancreatic tissue and ductal adenocarcinoma clusters. Our data provide evidence to suggest that acinar cell carcinomas and pancreatoblastomas are similar at the epigenetic level. These findings are consistent with genomic and clinical observations that mixed acinar neoplasms are closely related to pure acinar cell carcinomas rather than to neuroendocrine tumors or ductal adenocarcinomas.

Solid pancreatic masses in children: A review of current evidence and clinical challenges

Pancreatic tumors in children are infrequently encountered in clinical practice. Their non-specific clinical presentation and overlapping imaging characteristics often make an accurate preoperative diagnosis difficult. Tumors are categorized as epithelial or non-epithelial, with epithelial tumors further classified as tumors of the exocrine or endocrine pancreas. Although both are tumors of the exocrine pancreas, solid pseudopapillary neoplasm is the most prevalent solid pancreatic tumor in children, while pancreatoblastoma is the most common malignant tumor. Insulinoma is the most common pediatric pancreatic tumor of the endocrine pancreas. Malignant tumors require a complete, often radical, surgical resection. However, pancreatic parenchyma-sparing surgical procedures are utilized for benign tumors and low-grade malignancy to preserve gland function. This review will discuss the epidemiology, pathophysiology, clinical and diagnostic characteristics, and management options associated with both common and rare solid pancreatic masses in children. We will also discuss current challenges encountered in their evaluation and treatment.

Genetic Analysis of Pediatric Pancreatoblastoma: A Case Report

Pediatric pancreatoblastoma (PBL) is a rare disease, and the treatment of which is diverse. The molecular alteration in pancreatoblastoma is not very clear. A 7-year-old female who presented with intermittent abdominal pain, anorexia, and abdominal mass was admitted in our hospital. Pancreaticoduodenectomy, cholecystectomy, and retroperitoneal lymph node dissection were conducted. Immunohistochemistry results after surgery showed creatine kinase +, clusters differentiation 56 -, clusters differentiation 99 +, carcinoembryonic antigen -, periodic acid-Schiff +, B- catenin +, Ki-67 + 70%, progesterone receptor +, neuron-specific enolase -, vimentin -, and insulin -. According to the cell shape and the results of immunohistochemistry, the patient was diagnosed with PBL. The tumor tissue, adjacent tissue, and blood were collected. Mutation profiles were detected using next-generation sequencing technique with a panel of 704 genes. The child recovered well without complications postoperatively. There were 261 genes mutated in her plasma or tumor tissue (mutant frequency ≥1%). The adjacent tissue and plasma harbored the echinoderm microtubule-associated protein-like 4 gene-anaplastic lymphoma kinase fusion and tumor tissue harbored proto-oncogene receptor tyrosine kinase 1-solute carrier family 34 member A2 fusion. The gene alteration profiles of PBL patients warrant further investigations, which may provide new insight into the treatment of this disease.

[Rare pancreatic tumors]

Beyond pancreatic ductal adenocarcinoma, which is by far the most frequent pancreatic neoplasm, a great variety of tumors occur in the pancreas. They include solid and cystic masses and epithelial and nonepithelial neoplasms, and they show a great diversity in their biological behavior, ranging from benign tumors to highly aggressive neoplasms. As examples of rare pancreatic tumors, clinical, morphological, and molecular aspects of acinar cell carcinoma, pancreatoblastoma, solid pseudopapillary neoplasm, and serous cystic neoplasms are presented and discussed.

Survival Outcomes of Acinar Cell Pancreatic Cancer: A National Cancer Database Analysis

OBJECTIVES

Acinar cell pancreatic carcinomas (ACPCs) are rare neoplasms accounting for 1% to 2% of pancreatic tumors in adults. The objective of this study is to evaluate the benefit of chemotherapy in the adjuvant setting in resected ACPC and in the palliative setting for metastatic ACPC.

METHODS

Data were obtained from all US hospitals that contributed to the National Cancer Database between 2004 and 2014. Cases were identified using the histology code 8550.

RESULTS

A total of 593 patients with ACPC were identified. The mean age was 64.4 years (range, 18-90 years), with a male preponderance (72.8%, n = 432). Localized stage disease comprised 52.3% (n = 310) of patients. Among localized ACPC patients, 88.0% (n = 191) underwent surgery and 50.6% (n = 91) received adjuvant chemotherapy. The 5-year overall survival in those who received adjuvant treatment was slightly higher than those who did not receive adjuvant treatment (46.7% vs 44.8%, P = 0.3271). Among advanced-stage ACPC patients, 67.6% received chemotherapy, which translated into improved 5-year overall survival compared with no chemotherapy (8.1% vs 0%, P < 0.0001).

CONCLUSIONS

Chemotherapy in the palliative setting for advanced-stage ACPC patients was associated with improved survival. Adjuvant therapy did not translate into significant survival benefit.

Pancreatic panniculitis and elevated serum lipase in metastasized acinar cell carcinoma of the pancreas: A case report and review of literature

BACKGROUND

Pancreatic panniculitis is an extremely rare condition associated with different underlying pancreatic disorders and characterized by subcutaneous fat necrosis induced by elevated serum lipase levels. These lesions usually affect the lower extremities and may precede abdominal symptoms of pancreatic disease. Acinar cell carcinoma (ACC) of the pancreas is a rare pancreatic neoplasm, accounting for only 1%-2% of pancreatic tumors in adults.

CASE SUMMARY

We present the case of a 72-year-old man with ACC of the pancreatic head and synchronous liver metastases. Both the primary tumor and liver metastases were resected. Serum lipase was elevated before surgery and decreased to normal postoperatively. Rising serum lipase levels at follow-up led to the diagnosis of hepatic recurrence. This disease progression was then accompanied by pancreatic panniculitis, with subcutaneous fat necrosis and acute arthritis. To the best of our knowledge, only 4 cases have been reported in the literature and each showed a similar association of serum lipase levels with pancreatic panniculitis and progression of ACC.

CONCLUSION

Clinical symptoms and progression of ACC may correlate with serum lipase levels, suggesting potential usefulness as a follow-up biomarker.

Gene fusion characterisation of rare aggressive prostate cancer variants-adenosquamous carcinoma, pleomorphic giant-cell carcinoma, and sarcomatoid carcinoma: an analysis of 19 cases

AIMS

To evaluate the molecular underpinnings of the rare aggressive prostate cancer variants adenosquamous carcinoma, pleomorphic giant-cell carcinoma, and sarcomatoid carcinoma.

METHODS AND RESULTS

We retrieved 19 tumours with one or more variant(s), and performed ERG immunohistochemistry, a next-generation sequencing assay targeting recurrent gene fusions, and fluorescence in-situ hybridisation (FISH) for ERG and BRAF. Divergent differentiation included: sarcomatoid carcinoma (n = 10), adenosquamous carcinoma (n = 7), and pleomorphic giant-cell carcinoma (n = 7). Five patients had more than one variant. Four had variants only in metastases. ERG rearrangement was detected in nine (47%, seven via sequencing, showing TMPRSS2-ERG fusions and one GRHL2-ERG fusion, and two via FISH, showing rearrangement via deletion). ERG was immunohistochemically positive in the adenocarcinoma in eight of nine (89%) patients, but was immunohistochemically positive in the variant in only five of nine patients (56%, typically decreased). One patient had a false-positive ERG immunohistochemical result in the sarcomatoid component despite a negative FISH result. Two (11%) harboured BRAF fusions (FAM131A-BRAF and SND1-BRAF).

CONCLUSIONS

ERG fusions are present in these rare prostate cancer variants with a frequency close to that in conventional prostate cancer (9/19, 47%). ERG immunohistochemistry usually detects rearrangement in the adenocarcinoma, but is less sensitive for the variant histology, with weak to negative staining. Adenosquamous and sarcomatoid variants can, particularly, occur together. Molecular assessment may be an additional tool in selected cases to confirm the prostatic origin of unusual tumours. The presence of two BRAF rearrangements suggests that this gene fusion may be enriched in this setting, as RAF kinase fusions have been previously reported in 1-2% of prostate cancers.

Malignant epithelial/exocrine tumors of the pancreas

Pancreatic malignant exocrine tumors represent the most important cause of cancer-related death for pancreatic neoplasms. The most common tumor type in this category is represented by pancreatic ductal adenocarcinoma (PDAC), an ill defined, stroma-rich, scirrhous neoplasm with glandular differentiation. Here we present the relevant characteristics of the most important PDAC variants, namely adenosquamous carcinoma, colloid carcinoma, undifferentiated carcinoma, undifferentiated carcinoma with osteoclast-like giant cells, signet ring carcinoma, medullary carcinoma and hepatoid carcinoma. The other categories of malignant exocrine tumors, characterized by fleshy, stroma-poor, circumscribed neoplasms, include acinar cell carcinoma (pure and mixed), pancreatoblastoma, and solid pseudopapillary neoplasms. The most important macroscopic, histologic, immunohistochemical and molecular hallmarks of all these tumors, highlighting their key diagnostic/pathological features are presented. Lastly, standardized indications regarding gross sampling and how to compile a formal pathology report for pancreatic malignant exocrine tumors will be provided.

Characterization of 22 Canine Pancreatic Carcinomas and Review of Literature

Pancreatic carcinomas are rare in dogs and clinical signs are mostly non-specific. The literature on clinically and pathologically characterized canine exocrine pancreatic tumours is limited to 76 cases reported since 1963. This retrospective study analysed formalin-fixed samples of pancreatic carcinomas from 22 dogs, obtained during elective exploratory surgery (n = 16) or if the dog was humanely destroyed (n = 6). Tumours were diagnosed according to the World Health Organization classification of tumours of the pancreas of domestic animals. In seven cases, blood samples taken during or shortly before surgery were analysed for concentrations of alpha-amylase, 1,2-o-dilauryl-rac-glycero-3-glutaric acid-(6'-methylresorufin) ester lipase (DGGR lipase), C-reactive protein (CRP), alanine aminotransferase, glutamate dehydrogenase, alkaline phosphatase (ALP), canine trypsin-like immunoreactivity (cTLI) and canine pancreatic lipase immunoreactivity (cPLI). Neutrophil and lymphocyte numbers were determined as part of a complete blood count. Clinical signs were non-specific and included vomiting, inappetence and diarrhoea. Acinar carcinomas were most common (19/22) and observed growth patterns included: solid (n = 14), acinar (n = 5), clear cell (n = 3), mucinous (n = 2), trabecular (n = 1) or rosette-like (n = 1), occurring as a single pattern or in combination. Ductal carcinomas were identified in three cases. Pancreatitis was a common additional histological finding; five dogs had mild and nine dogs had severe pancreatitis. cPLI, DGGR lipase, cTLI and CRP were elevated in 5/5 acinar carcinomas. All liver enzymes were elevated in three of these five animals and ALP was increased in 4/5 dogs. Two dogs with ductal pancreatic carcinomas showed normal cPLI concentrations. One had increased CRP, liver enzymes and leucocytosis with neutrophilia, the other had elevated DGGR lipase and cTLI concentrations. Clinical findings in canine pancreatic carcinomas were non-specific and simultaneous inflammation can mask the detection of the underlying neoplasm in clinical examination and laboratory testing.

Diagnosis and treatment of pancreatoblastoma in children: a retrospective study in a single pediatric center

BACKGROUND

Pancreatoblastoma is a very rare malignant pancreatic tumor in children. Pancreatoblastoma is the most common pancreatic tumor in children less than 10 years of age, accounting for 25% of the pancreatic neoplasm. There were only a few published literatures about the standardized diagnostic and management protocol for PB in the last decade.

OBJECTIVE

To summarize our experience in the management of pancreatoblastoma in children and adolescents with emphasis on the presentation, diagnosis, treatment, and outcomes. A management strategy will also be discussed.

METHODS

This was a retrospective case-series study of all pancreatoblastoma in patients < 18 years of age who were treated at Beijing children's hospital (BCH) from January 2002-January 2015. The diagnoses of PB were confirmed by histopathology analysis of the resected specimen. The variables being analyzed included patient demographics, age at diagnosis, clinical presentation, tumor size, metastasis if present, tumor markers (AFP), type of surgery, length of follow-up, and outcome. The assessment of the tumor location, size, extent of the tumor, and distant metastasis was made by ultrasound (US), computed tomography (CT), and/or magnetic resonance imaging (MRI).

RESULT

21 patients with pancreatoblastoma were diagnosed at a median age of 4 years, 7 girls, and 14 boys. The diagnosis of pancreatoblastoma was identified by the histology examination. The most common syndrome was abdominal mass (n = 11), followed by abdominal pain (N = 10), elevated serum AFP levels were noted in almost all cases (17/18), 17 patients with disease initially unresectable on diagnosis accepted neo-adjuvant chemotherapy consisting of CDV, OPEC, PLADO, IEV, and AVCP. All patients underwent surgery, including pancreaticoduodenectomy (Whipple's procedure), the Pylorus-preserving pancreaticoduodenectomy (traverse-Longmire procedure), Spleen-preserving distal pancreatectomy, and distal pancreatectomy with en bloc splenectomy, Roux-en-Y end-to-end pancreatojejunostomy. In all, 13 children were disease free with a median follow-up of 53 months (range 11-156 months).

CONCLUSIONS

The pancreatoblastoma in children and adolescents is a malignant tumor. Complete resection combined with chemotherapy is associated with long-term survival. For the unresectable tumor at diagnosis, preoperative chemotherapy was recommended to reduce tumor volume. AFP is critical for diagnosis and monitoring the disease as a tumors marker.

Cytopathology and ultrastructure identification of primary hepatic acinar cell carcinoma: Case report

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Acinar cell carcinoma originating in the liver proper remains a diagnostic quandary.

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Non-specific imaging features may have led to prior misdiagnosis and poor outcomes.

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Ultrastructural electron microscopy represents a novel tool for identification.

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Heterotopia or metaplastic mechanisms may underlie hepatic acinar cell localization.

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The previous literature is summarized in context of the present case of hepatic ACC.

Introduction

A primary acinar cell carcinoma (ACC) of the liver was incidentally diagnosed in a clinically asymptomatic 80-year-old man. This study aimed to delineate critical diagnostic characteristics of an ACC originating uniquely from the liver to improve its future identification.

Presentation of case

Enhanced MRI revealed a heterogenous, cystic 7.7 × 11.1 × 10.4 cm tumour occupying hepatic segments II and III. The mass demonstrated mild diffuse enhancement in hepatic arterial phase with minimal portal venous washout in a liver without cirrhotic features. A central stellate T2-hyperintense necrotic scar and outer capsule were apparent. No primary lesion or metastasis outside the liver was discernable. Post-left hepatic lobectomy, the tumour immunophenotype was atypical for presumptive diagnoses of hepatocellular carcinoma (HCC) or cholangiocarcinoma. Extensive morphologic workup on electron microscopy definitively diagnosed primary hepatic ACC by establishing presence of secretory zymogen-like granules, intracytoplasmic microvilli and acinar cell differentiation. Cytopathology revealed cellular lumen expressing PAS-positive diastase-resistant granular cytoplasmic contents.

Discussion

This case showcased the novel utility of electron microscopy that was crucial in yielding the definitive diagnosis. The previous literature on hepatic ACC was compiled here in context of the present case. The mechanism of hepatic acinar cell localization was also discussed.

Conclusion

Primary hepatic ACC may easily be confused for other lesions due to nonspecific imaging patterns. Specifically, the presence of a central scar without risk factors for HCC can favour a diagnosis of benign entities such as focal nodular hyperplasia (FNH). Electron microscopy presents an important tool to identify primary hepatic ACC and may improve future patient outcomes.

Systemic Chemotherapy for Advanced Rare Pancreatic Histotype Tumors: A Retrospective Multicenter Analysis

OBJECTIVES

Two issues were put forth by clinicians in the management of the advanced stages of rare variants of pancreatic ductal adenocarcinoma and other exocrine histotypes with peculiar clinical and pathological features: Do chemotherapy regimens recommended in pancreatic ductal adenocarcinoma patients have a clinical activity in rare pancreatic tumors? Or should other chemotherapy combinations be considered in this subset of patients?

METHODS

We conducted a multicenter retrospective study that collected data from 2005 to 2016 at 14 Italian cancer centers with the aim to evaluate tumor response and time to progression for first- and second-line and overall survival.

RESULTS

Of approximately 4300 exocrine pancreatic cancer patients, 79 advanced cases affected by rare histological types were identified, with pancreatic acinar cell cancer (n = 23), pancreatic adenosquamous cancer (n = 16), and mucinous cystic neoplasm with an associated invasive mucinous cystadenocarcinoma (n = 15) most represented. Survival analyses for each subgroup in relation with the different chemotherapy regimens showed the lack of statistical significance correlations.

CONCLUSIONS

Because of the lack of clinical trials in patients affected by these rare pancreatic histotypes, only their molecular classification would help clinicians in future therapeutic choice.

Genetics of Pancreatic Neoplasms and Role of Screening

There is a wide spectrum of pancreatic neoplasms with characteristic genetic abnormalities, tumor pathways, and histopathology that primarily determine tumor biology, treatment response, and prognosis. Although most pancreatic tumors are sporadic, 10% of neoplasms occur in the setting of distinct hereditary syndromes. Detailed studies of these rare syndromes have allowed researchers to identify a myriad of specific genetic signatures of pancreatic tumors. A better understanding of tumor genomics may have significant clinical implications in the diagnosis and management of patients with pancreatic tumors. Evolving knowledge has paved the way to screening paradigms and protocols in individuals at higher risk of developing pancreatic tumors.

Adult pancreatoblastoma: A case report and clinicopathological review of the literature

PURPOSE

Our purpose was to report a case of adult pancreatoblastoma, and review the literature in order to assist clinicians in the management of the disease.

MATERIALS AND METHODS

The demographic, clinical, and imaging findings of 41 patients with pathologically proven pancreatoblastoma from 1986 to 2017 identified in PubMed were reviewed. The key words used for searching PubMed were: "pancreatoblastoma", "pancreatic tumor", and "adult pancreatoblastoma." We also reported the details of a case of adult pancreatoblastoma treated at our institution.

RESULTS

We identified 41 cases of adult pancreatoblastomas, and the mean age at diagnosis was 41.4 ± 17.4 years. Pancreatoblastomas occurred in the pancreatic head in 48.4% of patients, and in 39.0% of cases the tumor was >8 cm in diameter at diagnosis. Patient age and tumor size were similar between males and females (P = 0.59; P = 0.32, respectively). Metastases was present in 17 of the 41 adult patients (41.5%). No significant difference in age, sex, tumor size, and tumor location was found between patients with and without metastases (P = 0.57, 0.58, 0.64, 0.39, respectively).

CONCLUSION

Preoperative diagnosis of adult pancreatoblastoma is difficult because of the heterogeneous, variable cellular differentiation and atypical clinical and imaging features. A pancreatoblastoma should be considered when tumors in the pancreas are solid and cystic.

EGFR amplification induces sensitivity to antiEGFR therapy in pancreatic acinar cell carcinoma

Pancreatic acinar cell carcinoma (PACC) is a rare cancer. When the tumor is metastatic, few therapeutic options are available. Precision medicine using next-generation sequencing is defined by the administration of drugs based on the tumor genetic mutations. The usage of precision medicine for finding new therapeutic options for rare cancers is an emerging field. We have reported here the case of a patient bearing a multitreated metastatic PACC. This patient underwent somatic and constitutional exome analyses. The analyses revealed in the liver metastasis an amplification of the EGFR gene. Accordingly, the patient was treated with off-label usage of panitumumab. We observed rapid response with necrosis of the liver metastasis, while no efficacy was observed in the primary tumor. An exome analysis of the primary tumor revealed amplification of HER2 and MET with EGFR amplification. Such amplifications are known as a resistance mechanism to antiEGFR therapy. Our results suggest that exome analysis may be helpful to highlight targets in rare cancers, such as PACC. EGFR amplification in this pathology should be determined and could be used as a biomarker to propose antiEGFR therapy.

A FISH assay efficiently screens for BRAF gene rearrangements in pancreatic acinar-type neoplasms

Approximately 1-2% of pancreatic neoplasms are acinar cell carcinomas. Recently, BRAF gene rearrangements were identified in over 20% of acinar-type neoplasms, which included both pure acinar cell carcinomas and mixed carcinomas with acinar differentiation, using next-generation sequencing-based platforms, providing a potential therapeutic target for patients with these neoplasms. Thus, it is clinically important to develop a rapid, cost- and material-efficient assay to screen for BRAF gene fusions in pancreatic acinar-type neoplasms. We developed a dual color, break-apart FISH assay to detect BRAF gene rearrangements in these neoplasms and evaluated its performance in comparison to next-generation sequencing-based studies. A blinded BRAF rearrangement FISH investigation was performed on 31 acinar-type neoplasms that had been studied previously by next-generation sequencing-based analysis as well as on 18 additional acinar-type neoplasms that were accrued over the past 2 years. In total, BRAF fusions were identified in 12/49 (24%) acinar-type neoplasms by FISH. BRAF fusion partners were uncovered by using targeted next-generation sequencing studies in 11 FISH-positive cases that had sufficient material for next-generation sequencing studies. SND1 was the most frequent fusion partner involved in BRAF-fusion acinar-type neoplasms (50%), followed by HERPUD1 (18%). No BRAF fusions were identified by next-generation sequencing in any of the FISH-negative cases investigated. FISH analysis showed that BRAF rearrangements were diffusely present across tumor-rich areas in BRAF-fusion acinar-type neoplasms, which is consistent with an oncogenic driver alteration pattern. Thus, we demonstrated that, in comparison to targeted next-generation sequencing-based technologies, the FISH assay is highly sensitive and specific as well as time- and cost-efficient in the detection of BRAF fusions in acinar-type neoplasms. The FISH assay can be easily implemented in diagnostic settings to identify acinar-type neoplasms patients potentially suitable for targeted therapy to inhibit MAPK pathway activity.

Pancreatic acinar cell carcinoma: A review on molecular profiling of patient tumors

Pancreatic carcinomas with acinar differentiation are rare, accounting for 1%-2% of adult pancreatic tumors; they include pancreatic acinar cell carcinoma (PACC), pancreatoblastoma, and carcinomas of mixed differentiation. Patients with PACC have a prognosis better than pancreatic ductal adenocarcinomas but worse than pancreatic neuroendocrine tumors. Reports of overall survival range from 18 to 47 mo. A literature review on PACCs included comprehensive genomic profiling and whole exome sequencing on a series of more than 70 patients as well as other diagnostic studies including immunohistochemistry. Surgical resection of PACC is the preferred treatment for localized and resectable tumors. The efficacy of adjuvant treatment is unclear. Metastatic PACCs are generally not curable and treated with systemic chemotherapy. They are moderately responsive to chemotherapy with different regimens showing various degrees of response in case reports/series. Most of these regimens were developed to treat patients with pancreatic ductal adenocarcinomas or colorectal adenocarcinomas. Review of PACC's molecular profiling showed a number of gene alterations such as: SMAD4, BRAF, BRCA2, TP53, RB1, MEN1, JAK-1, BRCA-1, BRCA-2, and DNA mismatch repair abnormalities. PACCs had multiple somatic mutations with some targetable with available drugs. Therefore, molecular profiling of PACC should be an option for patients with refractory PACC.

Genome-wide genetic and epigenetic analyses of pancreatic acinar cell carcinomas reveal aberrations in genome stability

Pancreatic acinar cell carcinoma (ACC) is an aggressive exocrine tumor with largely unknown biology. Here, to identify potential targets for personalized treatment, we perform integrative genome-wide and epigenome-wide analyses. The results show frequently aberrant DNA methylation, abundant chromosomal amplifications and deletions, and mutational signatures suggesting defective DNA repair. In contrast to pancreatic ductal adenocarcinoma, no recurrent point mutations are detected. The tumor suppressors ID3, ARID1A, APC, and CDKN2A are frequently impaired also on the protein level and thus potentially affect ACC tumorigenesis. Consequently, this work identifies promising therapeutic targets in ACC for drugs recently approved for precision cancer therapy.

Pancreatoblastoma With Metastatic Retroperitoneal Lymph Node and PET/CT

A previously healthy 4-year-old girl presented with petechial rash and low platelet count. There were no other symptoms. On abdominal ultrasound, a 4.7-cm heterogeneous mass was demonstrated anterior to the left kidney. An abdominal MRI subsequently performed demonstrated a heterogeneously enhancing mass at the same location extending to the pancreas and spleen. A surgical biopsy of the mass was obtained. Pathology reported a malignant epithelioid neoplasm consistent with pancreatoblastoma. The mass demonstrated intense FDG uptake on PET and an FDG avid retrocaval lymph node.

Intraductal Tubulopapillary Neoplasm of the Pancreas: A Clinicopathologic and Immunohistochemical Analysis of 33 Cases

Intraductal tubulopapillary neoplasm (ITPN) is a relatively recently described member of the pancreatic intraductal neoplasm family. Thus, the literature on its histologic and immunohistochemical features, clinical behavior, and its similarities and differences from other pancreatic neoplasms is limited. Thirty-three cases of ITPN, the largest series to date, were identified. Immunohistochemical labeling for cytokeratins, glycoproteins, pancreatic enzymes, markers for intestinal and neuroendocrine differentiation, and antibodies associated with genetic alterations previously described in pancreatic neoplasms was performed. Clinicopathologic features and survival was assessed. Seventeen patients were female and 14 were male. Mean age was 55 years (range, 25 to 79 y). Median overall tumor size was 4.5 cm (range, 0.5 to 15 cm). Forty-five percent of the tumors occurred in the head, 32% in the body/tail, and 23% showed diffuse involvement. Microscopically, the tumors were characterized by intraductal nodules composed of tightly packed small tubular glands lined by cuboidal cells lacking apparent mucin. Although it was often challenging to determine its extent, invasion was present in 71%. Almost all tumors labeled for CAM5.2, CK7, and CK19; most expressed CA19.9, MUC1, and MUC6. CDX2, MUC2, trypsin, chymotrypsin, chromogranin, and synaptophysin were not expressed. SMAD4 expression was retained in 100%; p16 expression and p53 overexpression was seen in 33% and 27%, respectively. Follow-up information was available for 22 patients (median follow-up, 45 mo; range, 11 to 173 mo). Two patients with invasive carcinoma died of disease at 23 and 41 months, respectively. One patient died of unrelated causes at 49 months. Twelve patients were alive with disease. Seven patients were alive with no evidence of disease. The overall 1-, 3-, and 5-year survival rates were 100% in patients without an invasive component and 100%, 91%, and 71%, respectively, in patients with an invasive component (P=0.7). ITPN is a distinct clinicopathologic entity in the pancreas. Despite the difficulties of determining the extent of invasive carcinoma in many cases, the overall outcome seems to be relatively favorable and substantially better than that of conventional pancreatic ductal adenocarcinoma, even when only the cases with invasive carcinoma are considered.

Systematic Review and Case Series Report of Acinar Cell Carcinoma of the Pancreas

BACKGROUND

Acinar cell carcinoma of the pancreas is a rare malignancy representing less than 1% of all pancreatic malignancies.

METHODS

We report on a case series of 21 patients with acinar cell carcinoma of the pancreas treated at a high-volume quaternary center. A systematic review of the medical literature was performed that described typical therapeutic management approaches for acinar cell carcinoma of the pancreas and reported on disease control and survival rates. Data for the case series were obtained from a prospective database.

RESULTS

In our systematic review of 6 articles, study patients had a median age of 61 years, 66% were male, 52% had stage I/II disease, and 55% of lesions were located in the pancreatic head. The rates of median survival were approximately 47 months after resection with adjuvant therapy, 38 months for nonmetastatic, locally unresectable disease, and 17 months for metastatic disease treated with chemotherapy. Combination fluoropyrimidine-based chemotherapy regimens had better rates of disease control than other therapies. Our case series included 21 study patients, 14 of whom required resection and 7 who had metastatic disease. The rates of median survival were 40.2 ± 31.9 months in those who underwent surgery and were treated with adjuvant therapy and 13.8 ± 11.3 months for patients with metastatic disease.

CONCLUSIONS

Multidisciplinary treatment for acinar cell carcinoma of the pancreas should be considered due to the rarity of the disease and its lack of high-level therapeutic data. Progress in the molecular analysis of this tumor may improve outcomes through the use of personalized therapy based on underlying tumor mutations.

Chronic inflammation initiates multiple forms of K-Ras-independent mouse pancreatic cancer in the absence of TP53

Chronic inflammation (CI) is a risk factor for pancreatic cancer (PC) including the most common type, ductal adenocarcinoma (PDAC), but its role and the mechanisms involved are unclear. To investigate the role of CI in PC, we generated genetic mouse models with pancreatic specific CI in the presence or absence of TP53. Mice were engineered to express either cyclooxygenase-2 (COX-2) or IκB kinase-2 (IKK2), and TP53^+/+ or TP53^f/f specifically in adult pancreatic acinar cells by using a full-length pancreatic elastase promoter-driven Cre. Animals were followed for >80 weeks and pancreatic lesions were evaluated histologically and immunohistochemically. The presence of K-ras mutations was assessed by direct sequencing, locked nuclei acid (LNA)-based PCR, and immunohistochemistry. We observed that sustained COX-2/IKK2 expression caused histological abnormalities of pancreas, including increased immune cell infiltration, proliferation rate and DNA damage. A minority of animals with CI developed pre-neoplastic lesions, but cancer was not observed in any TP53^+/+ animals within 84 weeks. In contrast, all animals with CI-lacking TP53 developed various subtypes of PC, including acinar cell carcinoma, ductal adenocarcinoma, sarcomatoid carcinoma and neuroendocrine tumors, and all died within 65 weeks. No evidence of K-ras mutations was observed. Variations in the activity of the Hippo, pERK and c-Myc pathways were found in the diverse cancer subtypes. In summary, chronic inflammation is extremely inefficient at inducing PC in the presence of TP53. However, in the absence of TP53, CI leads to the development of several rare K-ras-independent forms of PC, with infrequent PDAC. This may help explain the rarity of PDAC in persons with chronic inflammatory conditions.

Immunohistochemical analysis of the Wnt/β-catenin signaling pathway in pancreatic neuroendocrine neoplasms

AIM: To investigate the role of the Wnt/β-catenin pathway in pancreatic neuroendocrine neoplasms (PanNENs).

METHODS: Tissue microarrays containing 88 PanNENs were immunohistochemically labeled with antibodies to β-catenin, E-cadherin, adenomatous polyposis coli (APC), chromogranin and synaptophysin. One case had only metastatic tumors resected, whereas others (n = 87) received pancreatectomy with or without partial hepatectomy. Pathology slides, demographic, clinicopathologic, and follow up data were reviewed. Patients’ demographics, clinicopathologic features, and immunohistochemical results from 87 primary tumors were compared between patients with low stage (stage I/II) and high stage (stage III/IV) tumors. In addition, correlation of immunohistochemical results from primary tumors with disease-specific survival (DSS) was evaluated.

RESULTS: Strong membranous β-catenin staining in the primary tumor was observed in all 13 stage III/IV PanNENs as compared to 47% (35/74) of stage I/II tumors (P < 0.01). However, the strong membranous β-catenin staining was unassociated with tumor grade or DSS. Decreased membranous β-catenin staining was associated with decreased membranous E-cadherin labeling. Nuclear β-catenin staining was seen in 15% (2/13) of stage III/IV PanNENs as compared to 0% (0/74) of stage I/II tumors (P = 0.02). The case with metastasectomy also only showed nuclear β-catenin staining. Two of the three cases with nuclear β-catenin staining were familial adenomatous polyposis (FAP) patients. Lack of APC expression was seen in 70% (57/81) of the cases, including the 3 cases with nuclear β-catenin staining. Expression of E-cadherin and APC in primary tumor was not correlated with tumor grade, tumor stage, or disease specific survival.

CONCLUSION: The Wnt/β-catenin pathway was altered in some PanNENs, but did not Impact DSS. PanNENs in FAP patients demonstrated nuclear β-catenin accumulation and loss of APC.

Expression of Markers of Hepatocellular Differentiation in Pancreatic Acinar Cell Neoplasms: A Potential Diagnostic Pitfall

OBJECTIVES

Pancreatic acinar cell carcinoma (ACC) is a rare tumor that frequently metastasizes to the liver and may present a diagnostic challenge due to its morphologic similarity to hepatocellular carcinoma. We investigated α-fetoprotein (AFP), hepatocyte paraffin antigen 1 (HepPar 1), glypican 3, arginase 1, and albumin messenger RNA (mRNA) in situ hybridization (ISH) in pancreatic neoplasms with ACC differentiation to assess their diagnostic value.

METHODS

AFP, HepPar 1, glypican 3, and arginase 1 immunohistochemical staining was performed on 28 ACCs using a tissue microarray. Albumin mRNA ISH was performed on full-faced sections.

RESULTS

Fifteen tumors were positive for at least one marker. Glypican 3 was positive in seven of 28, AFP in five 28, and albumin mRNA ISH in five of 20. None expressed arginase 1.

CONCLUSIONS

Hepatocellular differentiation markers, including albumin mRNA ISH, may be positive in ACC, but arginase 1 appears to be uniformly negative. Thus, its use may improve the accuracy in distinguishing these neoplasms from hepatocellular carcinoma. If ACC diagnosis is considered, acinar differentiation can be reliably demonstrated by trypsin/chymotrypsin.

KRAS Mutations in Canine and Feline Pancreatic Acinar Cell Carcinoma

Companion animals may serve as valuable models for studying human cancers. Although KRAS is the most commonly mutated gene in human ductal pancreatic cancers (57%), with mutations frequently occurring at codons 12, 13 and 61, human pancreatic acinar cell carcinomas (ACCs) lack activating KRAS mutations. In the present study, 32 pancreatic ACC samples obtained from 14 dogs and 18 cats, including seven metastases, were analyzed for six common activating KRAS mutations located in codons 12 (n = 5) and 13 (n = 1) using Sequenom MassARRAY. No KRAS mutations were found, suggesting that, similar to human pancreatic ACC, KRAS mutations do not play a critical role in feline or canine pancreatic ACC. Due to the similarity of the clinical disease in dogs and cats to that of man, this study confirms that companion animals offer potential as a suitable model for investigating this rare subtype of pancreatic carcinoma.

Metastatic Renal Cell Carcinoma to the Pancreas: A Review

The pancreas is an unusual site for tumor metastasis, accounting for only 2% to 5% of all malignancies affecting the pancreas. The more common metastases affecting the pancreas include renal cell carcinomas, melanomas, colorectal carcinomas, breast carcinomas, and sarcomas. Although pancreatic involvement by nonrenal malignancies indicates widespread systemic disease, metastatic renal cell carcinoma to the pancreas often represents an isolated event and is thus amenable to surgical resection, which is associated with long-term survival. As such, it is important to accurately diagnose pancreatic involvement by metastatic renal cell carcinoma on histology, especially given that renal cell carcinoma metastasis may manifest more than a decade after its initial presentation and diagnosis. In this review, we discuss the clinicopathologic findings of isolated renal cell carcinoma metastases of the pancreas, with special emphasis on separating metastatic renal cell carcinoma and its various differential diagnoses in the pancreas.

Novel patient-derived xenograft mouse model for pancreatic acinar cell carcinoma demonstrates single agent activity of oxaliplatin

BACKGROUND

Pancreatic acinar cell carcinoma (PACC) is a rare malignancy, accounting for <1 % of all pancreatic neoplasms. Very few retrospective studies are available to help guide management. We previously reported the case of a patient with metastatic PACC who achieved prolonged survival following doxorubicin treatment. Personalized treatment was based on molecular and in vitro data collected from primary cells developed from their liver metastasis. We now report the characterization of a patient derived tumor xenograft (PDTX) mouse model that originated from this patient's PACC liver metastasis.

METHODS

Fragments of biopsy tissue (5 mm(3)) from PACC liver metastasis were implanted into athymic nude mice. Tumors were grown and passaged from the host mice into new mice to be tested for therapeutic response. Immuno-histochemical (IHC) biomarkers were used to confirm that the PDTX model represents human PACC. The antitumor activities of multiple drugs (5-FU, irinotecan, oxaliplatin, gemcitabine, bevacizumab, erlotinib, doxorubicin and imatinib) were tested. Tumor size was measured over 74 days or until they reached an endpoint volume of ~800 mm(3). Tests to measure serum lipase levels and histological analyses of tumor tissues were also conducted to assess PACC progression and re-differentiation.

RESULTS

The model presented here expresses the same IHC markers found in human PACC. In the chemotherapy study, oxaliplatin produced a prolonged durable growth response associated with increased apoptosis, decreased serum lipase levels and increased healthy acinar cells. Bevacizumab also produced a significant growth response, but the effect was not prolonged as demonstrated by oxaliplatin treatment. The other chemotherapies had moderate to little effect, particularly after treatment ceased. Mutations in DNA repair genes are common in PACC and increase tumor susceptibility to oxaliplatin. To explore this we performed IHC and found no nuclear expression of BRCA2 in our model, indicating a mutation affecting nuclear localization. Gene sequencing confirms BRCA2 has a homozygous gene deletion on Exon 10, which frequently causes a protein truncation.

CONCLUSIONS

In summary, we report the development and characterization of the first and only preclinical PACC PDTX model. Here we show sustained anti-tumor activity of single agent oxaliplatin, a compound that is more effective in tumors that harbor mutations in DNA repair genes. Our data shows that BRCA2 is mutated in our PACC model, which could contribute to the oxaliplatin sensitivity observed. Further studies on this rare PACC model can serve to elucidate other novel therapies, biomarkers, and molecular mechanisms of signaling and drug resistance.

Pancreatic Acinar Cell Carcinoma

Pancreatic acinar cell carcinoma (ACC) is a rare malignant neoplasm that accounts for 1–2% of all pancreatic neoplasms. Here we report two cases of ACC and describe their clinical features, the therapies used to treat them, and their prognosis. The first patient was a 65-year-old woman who had an abdominal CT scan for a urinary infection. Fortuitously, a rounded and well-delimited corporeal pancreatic tumor was discovered. An endoscopic ultrasound (EUS)-guided fine needle aspiration revealed an ACC. During the puncture, a hypoechoic cavity appeared inside the lesion, corresponding to a probable necrotic area. Treatment consisted of a distal splenopancreatectomy. The second patient was a 75-year-old man who complained of abdominal pain. An abdominal CT scan showed a cephalic pancreatic lesion and two hepatic metastases. An EUS-guided fine needle aspiration showed a pancreatic ACC. The patient received chemotherapy with gemcitabine plus oxaliplatin (GEMOX regimen), which enabled an objective response after 6 cycles.

Pancreatic desmoid-type fibromatosis with beta-catenin gene mutation-Report of a case and review of the literature

We experienced a rare case of pancreatic desmoid-type fibromatosis (DTF) in a 75-year-old Japanese woman. She was asymptomatic but routine examination including ultrasonography revealed a mass in the abdomen. For precise examination, she was referred to the regional hospital. Computed tomography showed that the mass was protruding anteriorly from the left-sided pancreas. Because of the enlargement of the mass lesion, distal pancreatectomy with splenectomy was performed after about 3 months. Macroscopically, the mass was encapsulated and approximately 8cm in diameter. Histological examination revealed that spindle or blunt stellate cells were proliferating in parallel or storiform fashion with myxoid and fibrous background. The tumor cells did not show prominent atypia and mitoses were rarely seen, suggesting that the tumor was low grade or borderline. Immunohistochemistry showed obvious nuclear staining of beta-catenin. Furthermore, analysis of beta-catenin gene revealed that the tumor had a typical missense mutation of threonine to alanine at colon 41 (T41A) in exon 3. These findings confirmed the pathological diagnosis of DTF of the pancreas. To the best of our knowledge, 18 cases of pancreatic DTF have been reported in the English literature and beta-catenin gene mutation had been examined in only one case among them. Thus, our case is the 19th pancreatic DTF and the second case with confirmed beta-catenin gene mutation.

Adult pancreatoblastoma: A case report and review of the literature

The present study describes the case of a 24-year-old patient who presented with obstructive jaundice and weight loss, and was diagnosed with pancreatoblastoma (PB). Abdominal imaging studies revealed a heterogenous lesion of the pancreatic head with dilatation of the common bile duct. The patient underwent pancreaticoduodenectomy, however, three months after surgery multiple liver and bone metastases were identified on follow-up computed tomography scans. Despite treatment with four cycles of systemic chemotherapy and five courses of radiofrequency ablation, the patient succumbed due to tumour dissemination 13 months after initial diagnosis. PB is a malignant tumour of the pancreas that typically occurs in the pediatric population. The aim of the present study was to highlight the aggressive behavior of this rare clinical entity, focusing on the pitfalls of pre-operative diagnosis and the lack of management strategy guidelines in adults. Preoperative diagnosis of PB based on radiographic features may be difficult, as the imaging characteristics are non-specific. Furthermore, cytology may also be misleading, as the neoplasm consists of multiple cell lines (acinar, ductal and neuroendocrine cells) and diagnosis depends largely on the identification of the distinctive histological characteristic of squamoid corpuscles, which present as nests of flattened cells with a squamous appearance. Despite the use of surgical resection and adjuvant chemoradiotherapy for the treatment of this malignancy, its aggressive nature means that PB is associated with a poor prognosis in adult patients.

Genomic landscapes of pancreatic neoplasia

Pancreatic cancer is a deadly disease with a dismal prognosis. However, recent advances in sequencing and bioinformatic technology have led to the systematic characterization of the genomes of all major tumor types in the pancreas. This characterization has revealed the unique genomic landscape of each tumor type. This knowledge will pave the way for improved diagnostic and therapeutic approaches to pancreatic tumors that take advantage of the genetic alterations in these neoplasms.