Intracholecystic papillary neoplasm of gallbladder (ICPN) is a rare recently described gallbladder entity which particularly involve the body and fundus. It has been recognized as a distinct type of pre-invasive neoplasm of gallbladder by 2019 WHO. Most ICPNs are commonly seen in females (2:1), with patients age ranging between 24 and 94 years. Usually, patients present with right upper quadrant pain and half of the patients radiologically get diagnosed with gallbladder cancer. Papillary, tubular or tubulopapillary growth patterns are seen, with sessile/broad-based friable excrescences or prominent exophytic growth that usually measures ≥ 1 cm in diameter. The median size of the tumor is 2.2 cm, and it can be solitary or multifocal. They may have thin stalks, which can lead lesions to detach from the mucosal surface, also they may be mistaken as sludge during gross exam. Histologically low-grade dysplasia has abundant cytoplasm, small and monotonous nuclei with distinct nucleoli. The high-grade dysplasia present with architectural complexity and nuclear atypia. Four different morphologic patterns have been recognized (intestinal, biliary, gastric and oncocytic). Approximately 50 % of ICPN cases coexist with invasive adenocarcinoma at the time of the pathologic diagnosis. Extensive sampling and careful microscopic evaluation are vital in ICPN cases, since invasive carcinoma may not be grossly visible and invasive carcinoma may be found away from them.

The gallbladder adenocarcinoma in the background of ICPN itself is rare diagnosis; low grade follicular lymphoma involvement of the gallbladder coexisting with invasive adenocarcinoma in the background of ICPN is even scarcer.