76 year old female with one-month history of right lower quadrant abdominal pain. CT shows acute appendicitis. 
Diagnosis (adenoca = adenocarcinoma)
Answer: Goblet cell adenocarcinoma (GCA) is a rare and distinctive neoplasm of the appendix that accounts for <5% of all appendiceal neoplasms. Thought to be derived from the intestinal crypt base stem cells.
The cell of origin might explain the mixed staining pattern. These include:
All are correct, but "Mucin and Chromo" is probably most correct: histologically, GCAs are composed of discrete nests of goblet cells admixed with neuroendocrine secretory granules and occasional Paneth cells.
Because of this mixed pattern, what other names have been used for this neoplasm? (AcGCT = Adenocarcinoid Goblet-Cell Type;
Answer: all of the above. When confined to appendix, these are tumors are considered low-grade. Prognosis is better than appendiceal adenoca but worse than NET of the appendix. Well-diff examples are reportedly curable by appendectomy.
