Detection of High-Grade Pancreatic Intraepithelial Neoplasia without Morphological Changes of the Main Pancreatic Duct over a Long Period: Importance for Close Follow-Up for Confirmation

Abstract

Pancreatic intraepithelial neoplasia (PanIN) is a microscopic papillary noninvasive lesion arising from the pancreatic ductal epithelium. However, the natural history and time to progression of high-grade PanIN remain unclear. Herein, we report 2 cases of high-grade PanIN without morphological changes of the main pancreatic duct (MPD) over relatively long periods. In the first case, a 63-year-old man was identified with MPD dilation. Magnetic resonance cholangiopancreatography showed localized stenosis in the pancreatic body with distal MPD dilation. Endoscopic retrograde pancreatography (ERP) was attempted because of possible high-grade PanIN but was unsuccessful. At 15-month follow-up, there was no change in the form of the MPD in various images. However, ERP was re-performed because of possible high-grade PanIN, and cytology showed adenocarcinoma. Postoperative pathology indicated diffuse lesions corresponding to high-grade PanINs in the MPD stenosis and surrounding branches. Final diagnosis was high-grade PanIN. In the second case, a 77-year-old man was identified with MPD dilation. Magnetic resonance cholangiography showed localized stenosis in the MPD of the pancreatic head with distal MPD dilation. He was diagnosed with MPD stenosis caused by chronic pancreatitis, and further examination was not recommended. At 25 months, the patient was referred to our hospital because of a mild change in MPD dilation. ERP showed localized irregular stenosis in the MPD, and cytology showed suspected adenocarcinoma. Postoperative pathology indicated a localized lesion with high-grade PanIN in the branch duct around the MPD stenosis. Final diagnosis was high-grade PanIN. In conclusion, we report 2 cases of high-grade PanIN without morphological changes of the MPD over relatively long periods. Even if a definite diagnosis is not obtained at initial examination, a strict follow-up observational study should be performed. Re-examination, including ERP, should also be considered in cases with risk factors of pancreatic cancer, even if there is no change in MPD form.

Partial Pancreatic Parenchymal Atrophy Is a New Specific Finding to Diagnose Small Pancreatic Cancer (≤10 mm) Including Carcinoma in Situ: Comparison with Localized Benign Main Pancreatic Duct Stenosis Patients

“…Regarding this time window for five years, Yachida et al [ 24 ] reported the duration between the birth of cancer cells and metastasis could be estimated an average of 6.8 ± 3.4 years. Moreover, Yamao et al [ 25 ] and Kuruma et al [ 26 ] reported that CIS developed in patients without morphology change of MPD for a long time (2.1 years and 4.0 years, respectively). These previous studies support the view that our exclusion criteria for time window in pathologically-unproven benign MPD stenosis could be valid.…”

High signal intensity on diffusion-weighted magnetic resonance images is a useful finding for detecting early-stage pancreatic cancer

“…No effective strategies for detecting early-stage PDAC are established. Recent advances in imaging modalities, including contrast-enhanced computed tomography (CECT), magnetic resonance imaging (MRI), and endoscopic ultrasonography (EUS), allow for the observation of pancreatic CIS [5][6][7][8][9][10][11][12] and the potential detection of indirect imaging findings such as main pancreatic duct (MPD) dilatation, branch duct dilatation, substantial atrophy, and fat substitution of the pancreatic parenchyma for early diagnosis. Screening of patients with risk factors associated with PDAC, such as family history, hereditary pancreatitis, intraductal papillary mucinous neoplasm, diabetes, and smoking [13][14][15][16][17][18][19], will also enhance early detection.…”

Analysis of Progression Time in Pancreatic Cancer including Carcinoma In Situ Based on Magnetic Resonance Cholangiopancreatography Findings

“…However, recent genetic and experimental study suggests that transformation of high-grade pancreatic intraepithelial neoplasia (PanIN), a pre-cancerous lesion of PC, into invasive PC required a time period ranging from 3 to 5 years [5]. A few cases have been published in which definite early PC had developed during a long observation period after the initial detection of main pancreatic duct (MPD) stenosis [6,7]. Although these case reports strongly suggested a long-term onset of early PC, estimation of the tumor Diagnostics 2021, 11, 1858 2 of 14 progression time is very difficult because of the small number of reported patients being diagnosed with early PC.…”