Goblet cell adenocarcinoma of the appendix: An incidental finding of a rare tumor which was recently renamed in 2019 World Health Organization classification update

Abstract

Abstract Introduction/Objective Goblet cell adenocarcinoma (formerly goblet cell carcinoid) is a rare tumor almost exclusively involving the appendix. It is an amphicrine tumor consisting of both epithelial and neuroendocrine elements containing goblet cells. In the 2019 WHO classification update, GCC was reclassified as goblet cell adenocarcinoma of the appendix as it is recognized to have predominantly mucin secreting cells and a minor neuroendocrine component. Methods/Case Report A 72 year old,morbidly obese male presented with a 2 week history of abdominal pain and bilious vomiting. Imaging revealed a peri-appendiceal abscess. Due to the chronicity of his symptoms, he was treated conservatively with drainage of the abscess and intravenous antibiotics. He responded well and underwent elective laparoscopic appendectomy; at which time, the appendix appeared grossly unremarkable, measuring 5.1 x 0.9 x 0.3 cm with a wall thickness of 0.5 cm. Microscopically small nests and clusters of goblet cells circumferentially invaded dense collagenous stroma in the appendiceal wall. The neoplastic cells had large mucin vacuoles and small basally located nuclei. The cells were positive for CK20, CDX2, CD56, synaptophysin and focally positive for chromogranin. Ki-67 was 10%. CK7 was negative. These tumors are now graded and staged similar to colonic adenocarcinomas according to the 5 th edition of the World Health Organization Classification of Tumors - Digestive System Tumors. Results (if a Case Study enter NA) NA Conclusion This case demonstrates that this rare tumor may be an incidental finding in an elderly patient presenting with appendicitis; accurate diagnosis of this rare tumor may require submission of the entire appendix for microscopic evaluation.