Intracholecystic papillary neoplasm acquiring malignant characteristics and leading to multiple liver metastases: A case report

The mechanisms underlying the progression of intracholecystic papillary neoplasms (ICPNs) to gallbladder cancer and invasive cancer remain relatively unclear. In the present case, metastatic liver tumors were suspected in an 83‐year‐old man at presentation; however, the primary tumor was unknown. The patient died shortly thereafter as a result of rapid tumor progression. An autopsy revealed multiple liver, lung, and lymph node metastases. Additionally, a fragile papillary tumor with a high‐grade dysplastic epithelium with tubulopapillary morphology and admixed foci of a low‐grade dysplastic epithelium were detected at the fundus of the gallbladder. The well‐differentiated tubular adenocarcinoma had extensively invaded the wall's granular mucosal surface along with the solitary papillary tumor. Based on pathological findings, a diagnosis of an ICPN with an associated invasive carcinoma was established. This case is novel because it showed that an ICPN can progress aggressively. We report a case of invasive gallbladder cancer with multiple liver metastases derived from the intracholecystic papillary neoplasm (ICPN). Progression of invasive gallbladder cancer from ICPN could be followed pathologically. This case suggests that unresectable gallbladder cancers of ICPN origin may remain overlooked, potentially resulting in poor prognosis.