A Case of Primary Mucinous Adenocarcinoma of the Lateral Lower Eyelid

Purpose: We report a case of primary mucinous adenocarcinoma diagnosed in a patient presenting with a mass of the lower eyelid.Case summary: A 60-year-old man presenting with a mass on the left lower eyelid that had increased in size for 3 years was referred to our center after being diagnosed as mucinous adenocarcinoma. The mass was limited to the dermis and subcutaneous fat layer. The extent of the lesion was confirmed through frozen section examination, and tumor removal was performed. In immunohistochemistry, estrogen receptor, progesterone receptor, and cytokeratin-7 were positive, and cytokeratin-20 was negative. No metastasis was found, so it was diagnosed as primary mucinous adenocarcinoma of the eyelid. After surgery, adjuvant radiotherapy was administered to the tissues surrounding the lesion, and it did not recur during 12 months of follow-up period.Conclusions: Primary mucinous adenocarcinoma of the skin, especially of the eyelid, is rare, and it is important to differentiate it from metastatic mucinous adenocarcinoma of other organs. The authors diagnosed primary mucinous adenocarcinoma using immunohistochemistry, and we report how it was successfully treated through surgical excision and reconstruction of the eyelid.