Intracholecystic papillary neoplasm
Intracholecystic papillary neoplasms (ICPN), also known as intracholecystic papillary-tubular neoplasms, are rare, recently described, preinvasive neoplasms of the gallbladder.
On imaging, these lesions resemble adenomas of the gallbladder or have features suspicious for gallbladder carcinoma, which usually lead to cholecystectomy and diagnosis. Given those non-specific imaging features, they should be reported and managed as per the gallbladder polyp guidelines.
As the distinction of intracholecystic papillary neoplasms from gallbladder adenomas is not entirely clear, with important overlap between both entities, some authors have proposed that both conditions should be grouped under the same terminology . The last WHO classification is from 2010 and precedes these publications.
Intracholecystic papillary neoplasms are rare, corresponding to ~0.5% of all gallbladder neoplasms . They are more frequent in women in their 6 decade of life .
- in about 20% of cases
Most of the cases are asymptomatic, although abdominal pain has been reported .
Intracholecystic papillary neoplasms are tumors analogous to intraductal papillary neoplasms of the bile ducts (IPNB), intraductal papillary mucinous neoplasms (IPMN) of the pancreas and pancreatic intraductal tubulopapillary neoplasms (ITPN) .
Adsay et al. have proposed that all gallbladder preinvasive adenomas over 1 cm should be grouped under the term ICPN .
- papillary or tubulopapillary patterns
- high-grade dysplasia is frequent (up to 75% to 100%)
- an invasive component is also prevalent (up to ~72%)
- MUC1 expression is frequent
Although there are no large series in the literature to support an overall imaging pattern of these lesions, it is known that they present similar to large polyps, particularly adenomas, or to intraluminal masses suspicious for gallbladder carcinoma.
Treatment and prognosis
Most cases, if not all, will be confirmed after surgery, as intracholecystic papillary neoplasms will be managed by the gallbladder polyps guidelines or based on the suspicion of adenocarcinoma of the gallbladder .
Intracholecystic papillary neoplasm with an invasive component has a better prognosis compared to conventional adenocarcinoma of the gallbladder .