Diagnosing chronic pancreatitis by endoscopic ultrasound assessing the association between ultrasound and pathological findings: A narrative review

Abstract

Endoscopic ultrasound (EUS) is widely recognized for its non‐invasiveness and for its usefulness in chronic pancreatitis (CP) diagnosis, including early CP. Although it is desirable to obtain a definitive diagnosis of CP by tissue sampling with EUS‐guided fine needle aspiration, histopathological changes in CP are heterogeneous in terms of the extent and the distribution of lesions. Therefore, histopathological diagnosis of appropriate tissue sampling by EUS‐fine needle aspiration is expected to be difficult. Furthermore, it is virtually impossible to match EUS images with pathological sections, making direct contrast between EUS findings and pathology difficult. This narrative review presents a discussion of the diagnosis of CP/early CP by EUS, particularly assessing the association between ultrasound and pathological findings. Recently, the histological corroboration and correlation of EUS findings related to CP have been clarified by surgical specimens, including those obtained from animal studies. Furthermore, remarkable advances have occurred in the objective and quantitative diagnosis of pancreatic fibrosis by EUS‐elastography. Future technological advances in EUS are expected to improve the accuracy of diagnosis of pancreatic fibrosis at earlier stages.

Role of EUS in Early Chronic Pancreatitis

“…When at least 3 of such lobules are contiguously located in the body or tail region, the pa ern is defined as 'lobularity with honeycombing' in EUS. (32,33) (Figure 2)…”

Proposal and Validation of New Diagnostic Criteria for Diagnostic Weights of Endoultrasonographic Findings for Early Chronic Pancreatitis

“…Clinical physical findings are (1) repeated epigastric or back pain, (2) outlier of pancreatic enzyme levels in the serum or urine, (3) outlier of pancreatic exocrine function, (4) continuous heavy drinking of alcohol equivalent to or more than 60 g/day of pure ethanol (EtOH 60 g/day) or pancreatitis-related susceptibility genes, and (5) previous history of acute pancreatitis (AP). In addition, ECP is defined as three or more of the items (1) through (5). Cases with two findings from (1) to (5) and EUS findings of early CP are diagnosed as probable ECP.…”

“…In addition, ECP is defined as three or more of the items (1) through (5). Cases with two findings from (1) to (5) and EUS findings of early CP are diagnosed as probable ECP.…”

“…Consequently, even if an EUS-FNA is performed, it is uncertain whether the sampling site reflects the histopathology of CP/ECP. Fortunately, the correlation between the EUS findings and histopathological findings of CP/ECP has been clarified recently [ 5 ]. In other words, if the diagnostic performance of EUS findings, which is an important factor in the diagnosis of ECP/CP, could be increased, it might replace the histopathological gold standard.…”

The Role of Endoscopic Ultrasound in Early Chronic Pancreatitis

“…When these lobules are non-contiguous, the EUS pattern is described as 'lobularity without honeycombing'. When at least three of such lobules are contiguously located in the body or tail region, the pattern is defined as 'lobularity with honeycombing' in EUS [30,31]. (Figure 2) The exact histopathological correlation of lobularity is not precisely known.…”