[Clinicopathological characteristics of goblet cell adenocarcinoma of the appendix]

Objective: To investigate the clinicopathological characteristics of goblet cell adenocarcinoma (GCA) of the appendix. Methods: Seven cases of GCA were collected at the First Hospital of Peking University, Beijing, China from 2015 to 2018. Hematoxylin and eosin staining and immunohistochemical studies (EnVision method) were carried out on all cases. Three cases were examined using electron microscopy. Results: Based on the review of 7 patients with GCA, the mean age of presentation for GCA of the appendix was 58 years with 2 men and 5 women, including 3 cases of grade 1, 3 cases of grade 2 and 1 case of grade 3 GCAs. Six GCAs had a prominent pattern of submucosal growth and lacked the formation of a well-defined tumor border. One of the 7 tumors was located in the distal segment of the appendix. Perineural involvement and lymphatic invasion were seen in 6 tumors and 1 tumor, respectively. Immunohistochemically, the tumor cells were diffusely or focally positive for chromogranin A, synaptophysin, CD56, cytokeratin, carcinoembryonic antigen, cytokeratin 20, MLH1, MSH2, MSH6 and PMS2, while the Ki-67 index ranged from 5% to 50%.The expression levels and positive cell numbers of p53 in high-grade GCAs were higher than those in low-grade GCAs. In the 7 patients with available follow-up information (14‒46 months), 1 patient died and the other 6 were alive at the end of the follow-up. Conclusions: GCA of the appendix is a rare neoplasm that shares histological features of both adenocarcinoma and carcinoid tumor. Its biological behavior ranges from indolent to highly aggressive.