High-grade pancreatic intraepithelial neoplasia: A commentary of magnetic resonance cholangiopancreatography findings

Abstract

Commentary on the role of magnetic resonance cholangiopancreatography findings in diagnosing high grade pancreatic intraepithelial neoplasms.

Key Words: Magnetic resonance; Cholangiopancreatography; Pancreas; Intraepithelial neoplasms; Diagnosis

Core Tip: Magnetic resonance cholangiopancreatography can help in early identification and stratification of high grade pancreatic intraepithelial neoplasms.

TO THE EDITOR

We read with interest the case report by Furuya et al[1], on magnetic resonance cholangiopancreatography (MRCP) findings that helped in diagnosing high-grade pancreatic intraepithelial neoplasia (PanIN).

CASE SUMMARY

The authors presented a case of a 60-year-old female patient with pancreatic cysts detected during a follow-up for uterine cancer[1]. The patient had diabetes mellitus but no history of smoking, alcohol consumption, pancreatic neoplasm, or chronic pancreatitis in her family. Imaging examinations including contrast-enhanced computed tomography, endoscopic ultrasonography (EUS), and MRCP revealed a 5 mm cyst in the pancreatic tail with no evidence of a solid mass nor parenchymal atrophy. EUS also showed hyperechoic spots suggesting early pancreatitis. MRCP described an irregular narrowing of the main pancreatic duct (MPD), with no finding of distal/caudal duct dilation. Follow-up imaging revealed cyst growth and slight MPD dilation over time. Contrast-enhanced EUS and endoscopic retrograde cholangiopancreatography (ERCP) confirmed the findings of irregular MPD narrowing and slight dilation of the caudal portion of the duct. Serial pancreatic juice aspiration cytology examination found neoplastic cells consistent with adenocarcinoma, leading to a final diagnosis of high-grade PanIN. Patient treatment involved a distal pancreatectomy; the patient remained alive without relapse 17 months postoperatively.

DISCUSSION

Pancreatic cancer poses significant challenges in medical research due to its aggressive nature and poor prognosis. PanIN represents an early stage (stage 0) of pancreatic cancer, which is potentially curable if diagnosed early. Unlike typical tumors, PanIN does not form a mass, making its diagnosis challenging. Instead, it can only be identified through indirect findings such as MPD stricture, dilatation, pancreatic cysts, and pancreatic atrophy. The case illustrated by Furuya et al[1] highlights the challenges in diagnosing high-grade PanIN, particularly in cases with poor MPD visualization. Despite challenges in diagnostic strategies, serial cytology of pancreatic juice based on changes in MRCP findings over time proved effective in this case, emphasizing the need for an early diagnosis system for pancreatic cancer.

Morphological features

PanIN encompasses a range of morphological changes within the pancreatic ductal epithelium, providing valuable clues for early detection and prognostic assessment[2]. Microcysts, fibrosis, and parenchymal atrophy could be indicators of PanIN; in particular, microcysts that do not communicate with the MPD could serve as predictive factors[3]. A non-communicating microcyst can be defined as a round cyst with a diameter up to 5 mm which has no surrounding ducts[4-6]. Parenchymal atrophy can be considered when the largest antero-posterior thickness of the pancreas is less than 20 mm[7]. These Authors demonstrated an increase in microcyst prevalence with advancing PanIN stages, with PanIN-3 showing the highest incidence[2,3]. Moreover, the association of PanIN with adjacent parenchymal fibrosis highlights the interplay between precursor lesions and the pancreatic microenvironment, offering insights into pancreatic cancer pathogenesis.

The case report by Furuya et al[1] also underlines the importance of continuous patient monitoring and early intervention. Advanced imaging techniques, such as MRCP, have transformed PanIN diagnosis, allowing precise identification and longitudinal monitoring of patients. MRCP, being non-invasive, facilitates a comprehensive lesion evaluation, guiding the selection of patients for invasive procedures like ERCP. Moreover, identification of PanIN risk factors, including obesity and intrapancreatic fat deposition, is mandatory for an early diagnosis; these risk factors underscore the multifaceted nature of pancreatic carcinogenesis, necessitating a holistic approach to risk assessment[8].

Understanding PanIN pathogenesis and morphological features allows to obtain diagnostic algorithms, risk stratification, and therapeutic decisions. Incorporating imaging-based surveillance into clinical practice aids in early PanIN detection, enabling timely intervention and potentially avoiding disease progression. Additionally, recognizing PanIN manifestations across different pancreatic conditions underscores the need for nuanced differential diagnosis and management approaches.

CONCLUSION

However, despite diagnostic progresses, PanIN diagnosis remains difficult and tricky. Further studies on molecular mechanisms leading to PanIN progression, and exploration of novel biomarkers and radiomics features for early tumor detection are needed. Novel prospective and observational studies on patient follow-up are needed, also in order to refine imaging techniques to grant an early and better identification of PanIN, particularly grade 3.