Merkel cell carcinoma on the dorsalis pedis with both dot-like perinuclear and cytoplasmic patterns of CK20 positivity

Classically known to be a tumor of the head and neck region, primary Merkel cell carcinoma (MCC) has rarely been reported in the lower leg. The present case showed both dot‐like perinuclear and cytoplasmic patterns of CK20 positivity in the primary MCC. We propose that the presence of both dot‐like perinuclear and cytoplasmic patterns of CK20 could reflect the diversity of MCC origin from stem cell to mature Merkel cells in our patient.