Five years earlier, 84-year-old woman underwent screening ultrasonography revealing an 8 mm cyst in the pancreas body, which had rapidly increased in size within the last year. EUS showed a 22 mm pancreatic body unilocular cyst and a 7.3 x 4.5 mm-sized hypoechoic lesion just distal to it. The upstream pancreatic duct was mildly dilated and constricted at this lesion. Adenocarcinoma was suspected on pancreatic juice cytology, and the patient underwent distal pancreatectomy. The resected specimen consisted of a cyst with a smooth lining, surrounded by significant fibrosis, and acinar atrophy without malignancy. Hence, we note that a simple mucinous cyst may present identical imaging findings as pancreatic carcinoma in situ.
