"Pure" hepatoid tumors of the pancreas harboring CTNNB1 somatic mutations: a new entity among solid pseudopapillary neoplasms

Emerging pathological diagnostic strategies for solid pseudopapillary neoplasm of the pancreas: insights from omics and innovative techniques

Solid pseudopapillary neoplasm (SPN) of the pancreas is a rare, low-grade malignant tumor, representing 0.9-2.7% of all exocrine pancreatic tumors. SPN patients generally have a favorable prognosis with a 5-year survival rate exceeding 95% following complete surgical resection. Accurate diagnosis is crucial to avoid unnecessary treatments. Currently, SPN diagnosis relies on imaging techniques such as CT and MRI, along with immunohistochemical analysis of biopsy and resection samples. The main challenge in diagnosis is the potential inability to accurately identify recurrent or metastatic SPN, as well as 'malignant' SPN, due to the lack of specific biomarkers. Advances in high-throughput omics technologies, including genomics, transcriptomics, proteomics and metabolomics, have opened new avenues for identifying novel biomarkers for SPN. Additional, liquid biopsy techniques have enabled more comprehensive analysis of biosamples such as pancreatic cyst fluid, offering promising prospects for preoperative diagnosis. This review highlights recent research on SPN diagnosis, focusing on immunohistochemical markers, tissue sampling methods and the potential of omics approaches. It also discusses the challenges and opportunities in improving diagnostic accuracy, particularly for high-grade and metastatic SPNs.

Comprehensive Characterization of Intraductal Oncocytic Papillary Neoplasm of the Pancreas: A Systematic and Critical Review

Intraductal oncocytic papillary neoplasm (IOPN) of the pancreas is a recently recognized pancreatic tumor. Here, we aimed to determine its most essential features with the systematic review tool. PubMed, Scopus, and Embase were searched for studies reporting data on pancreatic IOPN. The clinicopathologic, immunohistochemical, and molecular data were extracted and summarized. Then, a comparative analysis of the molecular alterations of IOPN with those of pancreatic ductal adenocarcinoma and intraductal papillary mucinous neoplasm from reference cohorts (including The Cancer Genome Atlas) was conducted. The key findings from 414 IOPNs were as follows: 1) The male-to-female ratio was 1.5:1. Pancreatic head was the most common site (131/237; 55.3%), but a diffuse tumor extension involving more than one pancreatic segment was described in about 1 out of 5 cases (49/237; 20.6%). The mean size was 45.5 mm. An associated invasive carcinoma was present in 50% of cases (168/336). In those cases, most tumors were pT1 or pT2 and pN0 (>80%), and vascular invasion was uncommon (20.6%). Regarding survival, more than 90% of patients were alive after surgical resection. 2) Immunohistochemical and molecular features were as follows. The most commonly expressed mucins were MUC5AC (110/112; 98.2%) and MUC6 (78/84; 92.8%). Compared with pancreatic ductal adenocarcinoma and intraductal papillary mucinous neoplasm, the classic pancreatic drivers KRAS, TP53, CDKN2A, SMAD4, and GNAS were less altered in IOPN (P < .01). Moreover, fusions involving PRKACA or PRKACB gene were detected in all of the 68 cases examined, with PRKACB::ATP1B1 being the most common (27/68 cases; 39.7%). These genomic events emerged as an entity-defining molecular alteration of IOPN (P < .01). Thus, such fusions represent a promising biomarker for diagnostic purposes. Recent evidence also suggests their role in influencing the acquisition of oncocytic morphology. IOPN is a distinct pancreatic neoplasm with specific clinicopathologic and molecular features. Considering the clinical or prognostic implications, its recognition is essential for pathologists and, ultimately, patients' management.

Circadian transcriptome of pancreatic adenocarcinoma unravels chronotherapeutic targets

Pancreatic ductal adenocarcinoma (PDA) is a lethal cancer characterized by a poor outcome and an increasing incidence. A significant majority (>80%) of newly diagnosed cases are deemed unresectable, leaving chemotherapy as the sole viable option, though with only moderate success. This necessitates the identification of improved therapeutic options for PDA. We hypothesized that there are temporal variations in cancer-relevant processes within PDA tumors, offering insights into the optimal timing of drug administration - a concept termed chronotherapy. In this study, we explored the presence of the circadian transcriptome in PDA using patient-derived organoids and validated these findings by comparing PDA data from The Cancer Genome Atlas with noncancerous healthy pancreas data from GTEx. Several PDA-associated pathways (cell cycle, stress response, Rho GTPase signaling) and cancer driver hub genes (EGFR and JUN) exhibited a cancer-specific rhythmic pattern intricately linked to the circadian clock. Through the integration of multiple functional measurements for rhythmic cancer driver genes, we identified top chronotherapy targets and validated key findings in molecularly divergent pancreatic cancer cell lines. Testing the chemotherapeutic efficacy of clinically relevant drugs further revealed temporal variations that correlated with drug-target cycling. Collectively, our study unravels the PDA circadian transcriptome and highlights a potential approach for optimizing chrono-chemotherapeutic efficacy.

Comments and illustrations of the European Federation of Societies for Ultrasound in Medicine contrast-enhanced ultrasound guidelines. Rare pancreatic tumors, imaging features on transabdominal ultrasound and EUS with contrast enhancement: Rare epithelial pancreatic tumors: solid pseudopapillary neoplasm, acinar cell carcinoma, mixed neuroendocrine-non-neuroendocrine neoplasms, some rare subtypes of pancreatic adenocarcinoma and pancreatoblastoma

Rare malignant pancreatic lesions are systematically reported in this review. The focus is on the imaging appearance of the rare epithelial pancreatic tumors such as the solid pseudopapillary neoplasm, acinar cell carcinoma, rare subtypes of adenocarcinoma, and pancreatoblastoma as seen on ultrasound, EUS, and contrast-enhanced ultrasound or EUS. The present overview summarizes the data and shows that not every pancreatic tumor is likely to be the most common entities of ductal adenocarcinoma or neuroendocrine tumor.

Hepatoid adenocarcinoma-Clinicopathological features and molecular characteristics

Hepatoid adenocarcinoma (HAC) is a rare, malignant, extrahepatic tumor with histologic features similar to those of hepatocellular carcinoma. HAC is most often associated with elevated alpha-fetoprotein (AFP). HAC can occur in multiple organs, including the stomach, esophagus, colon, pancreas, lungs, and ovaries. HAC differs greatly from typical adenocarcinoma in terms of its biological aggression, poor prognosis, and clinicopathological characteristics. However, the mechanisms underlying its development and invasive metastasis remain unclear. The purpose of this review was to summarize the clinicopathological features, molecular traits, and molecular mechanisms driving the malignant phenotype of HAC, in order to support the clinical diagnosis and treatment of HAC.

Hepatoid tumors of the gastrointestinal/pancreatobiliary district: morphology, immunohistochemistry, and molecular profiles

Hepatoid tumors (HTs) histologically resemble hepatocellular carcinoma (HCC) but manifest outside the liver. Regarding immunohistochemistry (IHC), the classical markers of hepatoid differentiation are Hep Par-1, CD10, and arginase-1. This study provides a critical overview of HT in the gastrointestinal/biliopancreatic system, which is the most common site of origin. Gastric HTs are malignant neoplasms recognized by the current WHO classification as a variant of adenocarcinoma. In addition to the classic IHC markers, SALL4 and claudin-6 can help exclude a metastatic HCC at this site. Next-generation sequencing revealed the most common alterations, including TP53 mutation, microsatellite instability (MSI), and Her2 amplification. Esophageal HTs are exceptionally rare and usually arise in the context of Barrett's esophagus. In the intestine, HTs are classified within the adenocarcinoma spectrum and manifest more often in the background of inflammatory bowel disease. Regarding their molecular profile, recurrent alterations included MSI and NCOA4-RET fusions. In the pancreas, the current WHO classification acknowledges HT only as a possible variant of ductal adenocarcinoma, characterized by a poor prognosis. However, at this site, neuroendocrine tumors (NETs) and solid pseudopapillary neoplasms (SPNs) may also show hepatoid differentiation. Hepatoid NETs show aggressive behavior, whereas hepatoid SPNs harbor CTNNB1 mutations and are characterized by an indolent clinical course. Lastly, biliary HTs belong to the adenocarcinoma category and usually show a poor prognosis. In conclusion, gastrointestinal/pancreatobiliary HTs show specific histomolecular features, which should be considered for improving routine diagnostic activity and clinical management.