Focal Parenchymal Atrophy and Fat Replacement Are Clues for Early Diagnosis of Pancreatic Cancer with Abnormalities of the Main Pancreatic Duct

Abstract

Pancreatic cancer is one of the most dangerous solid tumors, but its early diagnosis is difficult. The abnormality of the main pancreatic duct (MPD), such as a single localized stricture and upstream dilatation, might be useful in the early detection of pancreatic cancer. However, these findings are often observed in benign inflammatory cases. This study aimed to clarify whether early pancreatic cancer presenting MPD abnormalities has characteristic features different from those of benign cases. This is a single-center, retrospective study. We analyzed 20 patients who underwent pancreatectomy presenting with a single, localized MPD stricture without identifiable masses on imaging: 10 patients with pancreatic ductal adenocarcinoma (cancer group; 6 with stage 0 and 4 with stage I) and 10 patients with benign strictures (benign group; 8 with inflammation and 2 with low-grade pancreatic intraepithelial neoplasms). Pancreatectomy was performed in these benign cases because high-grade intraepithelial neoplasm was suspected. Although the proportion of patients with diabetes mellitus tended to be higher in the cancer group (6/10) than that in the benign group (1/10) (P = 0.058), other clinical characteristics were not different between the groups. Preoperative cytological malignancies were detected in four patients in the cancer group (4/10) but not in the benign group (P = 0.09). Focal parenchymal atrophy and fat replacement were more frequently detected on computed tomography in the cancer group (7/10) than in the benign group (1/10) (P = 0.02). In conclusion, focal parenchymal atrophy and fat replacement may provide clues for the early diagnosis of pancreatic cancer.

Focal Parenchymal Atrophy of the Pancreas Is Frequently Observed on Pre-Diagnostic Computed Tomography in Patients with Pancreatic Cancer: A Case-Control Study

“…In this case–control study, we showed that FPA, which has been reported as a characteristic imaging sign of early stage PDAC [ 13 , 14 , 15 ], was observed in about one-third of the patients at least 6 months before PDAC diagnosis ( Figure 3 ). FPA was more frequently observed in patients with PDAC than sex- and age-matched controls without PDAC.…”

“…PDAC in the uncinate process, especially at PDAC at an early stage, can be overlooked on imaging owing to the absence of biliary or pancreatic ductal dilatation [ 11 ]. MPD dilation, which is another important clue for the early diagnosis of PDAC [ 11 , 12 , 13 ], is recognized more easily in the pancreatic body and tail than in the pancreatic head because MPD is intact in the pancreatic head [ 13 ]. Notably, Matsudo et al [ 25 ] reported that carcinoma in situ was observed more frequently in the pancreatic body and tail than in the pancreatic head in autopsied cases, suggesting that the mechanism of carcinogenesis differs depending on the tumor location in the pancreas.…”

“…In cases with very early stage PDAC, including stage 0, imaging modalities usually cannot identify the mass, and only secondary findings might provide a clue. Main pancreatic duct (MPD) abnormalities, such as localized stricture/cut-off with subsequent upstream dilatation, might be key secondary findings for the early diagnosis of PDAC [ 10 , 11 , 12 , 13 ]. However, MPD abnormalities are not specific to PDAC and are often observed in benign pancreatic diseases.…”

“…Identification of imaging signs that are more specific to PDAC is urgently needed. Recently, several studies have shown that focal parenchymal atrophy (FPA) of the pancreas is a characteristic imaging finding revealed on CT performed in patients with early stage PDAC, including those with stage 0 PDAC [ 13 , 14 , 15 ]. Miura et al [ 13 ] reported that FPA was observed in 7/10 (70%) patients with early stage PDAC but only in 1/10 (10%) patients with benign MPD stricture/dilatation.…”

“…Recently, several studies have shown that focal parenchymal atrophy (FPA) of the pancreas is a characteristic imaging finding revealed on CT performed in patients with early stage PDAC, including those with stage 0 PDAC [ 13 , 14 , 15 ]. Miura et al [ 13 ] reported that FPA was observed in 7/10 (70%) patients with early stage PDAC but only in 1/10 (10%) patients with benign MPD stricture/dilatation. Yamao et al [ 14 ] reported that FPA was identified in 11/24 (45.8%) patients with small PDAC measuring less than 10 mm but only in 2/28 (7.1%) patients with benign MPD stenosis.…”