简介：AbstractIntroduction:Merkel cell carcinoma (MCC) is a rare, aggressive cutaneous malignancy, and its pathogenesis might relate to ultraviolet light and Merkel cell polyomavirus infection. MCC in the Chinese population is uncommon.Here, we present a case of MCC that occurred based on widespread actinic keratosis (AK) in a Chinese female.Case report:An 82-year-old woman presented with two rapidly enlarging and rupture lesions on the face for 1 year. Biopsy was suggestive of squamous cell carcinoma (SCC) on the forehead and MCC on the left cheek. The patient had a history of generalized AK for 3 years. The lesion on the left cheek was also revealed as an AK by histopathological examination 1 year ago. Complete surgical resection was performed to remove the two malignancies.Discussion:The co-occurrence of AK, SCC, and MCC in a Chinese woman is unusual. Immunohistopathological examination is vital for correct diagnosis. The three tumors, in this case, may originate from two different precursor cells and are affected by the same carcinogen. Alternatively, they may come from the same pluripotent epidermal stem cells, and chronic exposure to ultraviolet light and Merkel cell polyomavirus lead to the formation of different types of tumors. The coexist of MCC with other cutaneous tumors provided a train of thought for exploring the origin of MCC.Conclusion:We reported a rare co-existence phenomenon of MCC associated with AK and SCC. Hence, long-term follow-up and early treatment are imperative for patients with premalignant lesions, such as widespread AK.