
Transmission electron microscopy of colonic epithelium. (A) Cap polyposis: the thick superficial layer of mucus is in continuity with the mucus of goblet cells, but does not adhere to the cytoplasmic membrane of epithelial cells; mucus droplets coalesce. (B) Normal colon: the mucus is only found within the goblet cells; well formed mucus droplets are found from the bottom to the apex of the goblets.








