A Case of Pancreatic Carcinoma in situ Diagnosed by Repeated Pancreatic Juice Cytology

Repeated pancreatic juice cytology via endoscopic nasopancreatic drainage (ENPD) has a high diagnostic yield and might be useful for the diagnosis of early-stage pancreatic cancer. A 67-year-old man presented with a pancreatic cyst occasionally detectable in the body of the pancreas by ultrasonography (US). No obvious pancreatic tumor was detected by US, computed tomography (CT), magnetic resonance cholangiopancreatography, and endoscopic ultrasound (EUS) (although the latter did reveal a weak, low echoic area). Endoscopic retrograde pancreatography showed irregular narrowing of the main pancreatic duct (MPD) at the pancreatic body. Pancreatic juice cytology was also performed, but did not give evidence of a malignancy. Therefore, the patient was followed up. CT and EUS performed after 3 months showed the same findings as did endoscopic retrograde pancreatography; however, the results of repeated pancreatic juice cytology performed via ENPD tube revealed a suspected malignancy on 2 of 6 occasions. Therefore, we performed a central pancreatectomy. Histopathological examination of a resected specimen revealed carcinoma in situ in the narrow MPD at the body of the pancreas. In the current case, repeated pancreatic juice cytology via ENPD was effective. A weak low echoic area around the MPD stricture on EUS might be related to the inflammatory change accompanying carcinoma in situ of the pancreas.