*Squamous Cell Carcinoma (SCC)* – malignant proliferation of squamous cells; *most common worldwide* – way to remember is that the rest of the world smokes more than USA *Adenocarcinoma* – malignant proliferation of glands; *most common in USA* *Regardless of histology, 60% of tumors are polypoid or exophytic on gross examination*. More test answers on https://studyhippo.com/gi-cancers-tumors/