Skin - Characteristic dot-like Cytokeratin 20 immunostaining in a Merkel cell carcinoma.

Colon - Colorectal adenocarcinoma with strong Cytokeratin 20 immunostaining.

Colon - Colorectal adenocarcinoma with strong Cytokeratin 20 positivity of all tumor cells.

Uterus - Endometroid carcinoma of the endometrium with strong Cytokeratin 20 positivity.

Stomach - Gastric adenocarcinoma with strong Cytokeratin 20 positivity of all tumor cells.

Prostate - Moderate to strong Cytokeratin 20 immunostaining of few tumor cells in an adenocarcinoma (Gleason 5+5).

Ovary - Mucinous carcinoma with strong Cytokeratin 20 immunostaining in all cells.

Ovary - Strong Cytokeratin 20 positivity in a mucinous carcinoma.

Stomach - Strong Cytokeratin 20 positivity of all tumor cells diffusely growing gastric adenocarcinoma.