Pancreatic ductal adenocarcinoma originating from focal pancreatic parenchymal atrophy demonstrated by transabdominal ultrasonography.

In this report, we present an 80-year-old man referred for evaluation of a pancreatic mass detected by transabdominal ultrasonography during health screening. Additional examinations revealed severe, long-segment focal atrophy from the pancreatic head to the body, appearing as a cord-like hypoechoic lesion on transabdominal and endoscopic ultrasonography. Although cytological examination of pancreatic juice was recommended, the patient opted for a follow-up. Three years later, a hypoechoic mass with upstream main pancreatic duct dilatation developed in the atrophic region. Cytological examination of pancreatic juice revealed adenocarcinoma, and pancreaticoduodenectomy was performed. Histopathology revealed Stage IIB invasive ductal carcinoma and carcinoma in situ within the atrophic region. Retrospective review showed that focal atrophy was present on transabdominal ultrasonography 11 years before the invasive carcinoma mass appeared, progressing without main pancreatic duct dilatation until its development. During follow-up of focal atrophy, early diagnosis of carcinoma in situ or microinvasive carcinoma before main pancreatic duct dilatation is crucial. The present case suggests that severe, long-segment focal pancreatic parenchymal atrophy can be detected by transabdominal ultrasonography and that carcinoma in situ within the focal pancreatic parenchymal atrophy may progress to invasive carcinoma.