An aggressive type of endocrine tumor of the appendix presenting equally in males and females in the fifth decade of life and manifesting with a palpable mass and abdominal pain or acute appendicitis. Metastasis to the ovaries, peritoneum or right colon has usually already occurred in half of patients at the time of diagnosis. The disease is Monarch Disease Ontology identifier MONDO_0018017 (goblet cell carcinoma). Also known as: GCC, Goblet Cell Adenocarcinoma, appendix adenocarcinoid tumor, appendix adenocarcinoid tumour, appendix goblet cell carcinoid, appendix goblet cell carcinoid tumor, appendix goblet cell carcinoid tumour, appendix mixed carcinoid-adenocarcinoma.