KRT20 and colon mucinous adenocarcinoma: PMA has the pathological features of cotyloid or columnar tumor cells with abundant mucus in the cytoplasm, karyons at the fundus, small volume, and lower heteromorphism than non-mucinous adenocarcinoma.[8] The positivity rates of PMA’s main immunologic markers are approximately 90% for CK7, 50% for recombinant cytokeratin 20, and 9% for caudal-related homeobox transcription factor 2.[9] In the case reported here, the patient presented with pathological features in accordance with PMA, and CK7 immunohistochemical stain showed a positive result.