Intracholecystic Tubular Non-Mucinous Neoplasm: A Distinct Entity

Abstract

Abstract Introduction/Objective Intracholecystic tubular non-mucinous neoplasm (ICTN) of the gallbladder is a pre-invasive high-grade tumor of non-mucinous tubules which is a rare entity. Histologic morphology distinguishes this tumor from other more common gallbladder neoplasms like intracholecystic papillary neoplasm (ICPN) or gallbladder pyloric adenoma. Methods/Case Report A 62-year-old female with no significant past medical history was found to have elevated transaminase in routine lab work. Ultrasound incidentally revealed a pedunculated 1.7 cm polyp in the gallbladder, along with numerous smaller and unmeasured polyps. Six months later, a repeat ultrasound revealed multiple echogenic polyps with the largest polyp measuring 2 cm. She had a laparoscopic cholecystectomy. During surgery, the contents of the polyp were iatrogenically expulsed were submitted as a seperate specimen. Grossly, the gallbladder contents consisted of multiple irregular red soft tissue fragments measuring up to 2 cm, and the gallbladder had an attached cystic lymph node and diffuse small yellow polyps along the wall. The gallbladder and node were entirely evaluated microscopically and revealed diffuse cholesterolosis with cholesterol polyps without dysplasia. The gallbladder content revealed a polypoid neoloplasm with cauliflower-like surfaces, back-to-back tubules, and squamous morules. The lining epithelial cells are cuboidal in shape with vesicular pale nuclei with prominent nucleoli and scant cytoplasm. No papillary structures with fibrovascular core were identified. These findings confirmed the diagnosis of ICTN. Results (if a Case Study enter NA) NA Conclusion ICTN commonly presents as detached sludge mimicking granular material within the gallbladder lumen and can be a “disappearing” polyp. There is a clear distinction between ICTN and ICPN based on histological features. ICTN is characterized exclusively by high-grade features, while ICPN can be either low-grade or high-grade with high risk of invasion. ICTN is characterized by pedunculated polyps with a thin stalk and multilobulated growth, typically in the background of a relatively unremarkable gallbladder with a crowded proliferation of small tubular units without a fibrovascular core. Pyloric gland adenomas usually don’t show dysplasia and are less than 1 cm. It is important to submit any identified content of the gallbladder. Keeping this rare entity in mind as a differential diagnosis is essential for gallbladder neoplasms.