A Case of Intracystic Papillary Neoplasm With an Associated Invasive Adenocarcinoma

Intracystic papillary neoplasm (ICPN) is a preinvasive neoplasm of the gallbladder. Preoperative discrimination between ICPN and gallbladder cancer (GC) is difficult. The standard surgical strategy for ICPN has not yet been established. Herein, we report a case of ICPN with an associated invasive adenocarcinoma. A gallbladder tumor was detected by abdominal ultrasonography in an asymptomatic 69-year-old man, and he was referred to our hospital. Although computed tomography (CT), endoscopic ultrasonography, and magnetic resonance imaging findings in the present case were similar to those for GC, positron emission tomography-CT revealed that fluorodeoxyglucose (FDG) did not accumulate within the tumor. These imaging features suggested that patient was suspected to have GC with serosal invasion, and he underwent extended cholecystectomy and D2 lymph node dissection. He did not develop any postoperative complications, and he was discharged on postoperative day 7. There was no evidence of recurrence for 20 months after surgery. Histopathologic examination confirmed ICPN with an associated invasive adenocarcinoma. Because a previous study reported that almost half of ICPNs more than 1.0 cm in size often developed invasive cancer as our case, ICPNs more than 1.0 cm should be suspected of developing invasive carcinoma regardless of positive or negative accumulation of FDG.