The diagnostic approach to solid pancreatic masses has significantly evolved from the era when a focal pancreatic mass was almost synonymous to pancreatic ductal adenocarcinoma, to a wide spectrum of pancreatic lesions, some of which have good prognosis. With the advent of advanced diagnostic tools, particularly refined imaging and tissue acquisition techniques, a broader spectrum of differential diagnoses has been recognized, encompassing conditions ranging from neuroendocrine tumors or inflammatory masses, to rare entities like metastatic clear cell sarcoma or solitary fibrous tumors. We herein discuss case reports of some rare pancreatic lesions, which were diagnosed by combining clinical and imaging features and endoscopic ultrasound-guided tissue sampling and confirmed on surgical specimens. Further reports on these rare pancreatic tumors will contribute to a better understanding of their pathogenesis and effective management.

Acute pancreatitis is the leading cause of inpatient care among gastrointestinal conditions. Despite early intervention, one-third of patients experience recurrent acute pancreatitis (RAP). A comprehensive diagnostic approach is warranted to identify and treat underlying factors in order to prevent recurrence. RAP is most frequent among men aged 30-40, smokers, and in those with excessive alcohol consumption. To identify the etiology is paramount to stratify patients according to their individual risk of RAP and for predicting an eventual evolution to chronic pancreatitis. Although the initial management of acute pancreatitis is widely homogeneous according to established guidelines, there are no defined protocols to investigate RAP. In the present editorial article we propose a structured algorithm with precise recommendations to investigate the etiology RAP as part of routine clinical practice. Although there are relevant knowledge gaps in this disease, we believe that our guidance would contribute for a more homogenous diagnostic approach of RAP in clinical practice.

Differential diagnosis of pancreatic solid lesion (PSL) and prognosis of pancreatic cancer (PC) is a clinical challenge. We aimed to explore the differential diagnostic value of sound speed (SS) obtained from endoscopic ultrasonography (EUS) in PSL and the prognostic value of SS in PC.

Patients with PSL in The Third Xiangya Hospital of Central South University from March 2019 to October 2019 were prospectively enrolled, who obtained SS from PSL. Patients were divided into the PC group and the pancreatic benign lesion (PBL) group. SS1 is the SS of lesions and SS2 is the SS of normal tissues adjacent to lesions. Ratio1 is equal to SS1 divided by SS2 of PSL (ratio1 = SS1/SS2).

Eighty patients were enrolled (24 PBL patients, 56 PC patients). SS1 and ratio1 in PC group were higher compared with PBL group (SS1:1568.00 vs. 1550.00, Z = -2.066, p = 0.039; ratio1: 1.0110 vs. 1.0051, Z = -3.391, p = 0.001). The SS1 in PC (Z = -6.503, p < 0.001) was higher compared to SS2. In the nonsurgical group of PC, low ratio1 predicted high overall survival (OS) (7.000 months vs. 4.000 months; p = 0.039). In the surgical group of PC, low SS1 was associated with low median OS (4.000 months vs. 12.000 months; p = 0.033).

SS plays a vital role in distinguishing between PBL and PC. Higher SS1 and ratio1 obtained by EUS are more related to PC than PBL. In PC patients, high SS1 may predict pancreatic lesions. In the nonsurgical group of PC, low ratio1 may predict high OS. However, in the surgical group of PC, low SS1 may predict low OS.

Pancreatic cancer (PC) is a dangerous malignancy with a high mortality rate. Diagnosing PC at an early stage is difficult, and approximately 5% of the patients survive for 5 years. Microsatellite instability (MSI) plays an important role in colorectal cancer (CRC) for prognosis and immunotherapy. Evaluation of MSI status is important as it is recognized biomarker for the positive response of immune checkpoint blockade therapy in cancer. To our knowledge, there is no report yet on the prevalence of MSI in Korean PC patients. Studies have reported conflicting prevalence of MSI in PC.

Therefore, to improve the likelihood of MSI identification in PC, we included 133 patients with PC; paired tumor and normal tissue DNA were isolated and MSI was analyzed using Promega panel and immunohistochemistry (IHC) was also performed.

Our results from the Promega panel indicated that one (0.7%) tumor was MSI-high (MSI-H), 13 (9.8%) were MSI-low (MSI-L), and 119 (89.5%) were microsatellite stable (MSS). IHC result also confirmed dMMR in only one sample.

The finding of low incidence of MSI-H observed by the Promega panel also matched IHC results, so this study suggested that in Korean PC patients, MSI prevalence is infrequent.

The early detection of pancreatic ductal adenocarcinoma (PDAC) dramatically improves outcome. All available state-of-the-art imaging methods allow early detection with EUS being the best technique for exclusion of PDAC and detection of very early PDAC. Etiological differentiation of small SPL is important to guide individually tailored patients' management including radical surgery in resectable PDAC, medical (neoadjuvant or palliative intended) treatment in patients with non-resectable malignancy, pancreatic parenchyma saving strategies in some non-PDAC, and follow-up in particular in low-grade PanNEN or other small benign lesions. Multimodality EUS imaging including B-Mode assessment, elastography, contrast-enhancement and EUS-guided sampling is the most appropriate technique for diagnosis and risk assessment of small SPL. We present a review discussing modern (endoscopic) ultrasound imaging techniques including contrast enhanced ultrasound and elastography for the early detection and characterization of solid pancreatic lesions.