Merkel cell carcinoma co-existent with sebaceous carcinoma of the eyelid.

Merkel cell carcinoma is occasionally associated with other types of cutaneous malignancies including squamous cell carcinoma, basal cell carcinoma and lentigo maligna. We report a case of Merkel cell carcinoma co-existent with sebaceous carcinoma in the right upper eyelid of a 61-year-old Japanese man. Histopathologically, the resected tumor consisted of three nodules located in the tarsal plate, showing two distinct histopathological types. Two nodules were Merkel cell carcinoma and located in the proximal part of the palpebral conjunctiva. The third was sebaceous carcinoma located in the distal transitional zone between the epidermis and the conjunctiva. No features of transition between these two components were noted. Metastatic deposits were identified in the regional lymph nodes, which solely consisted of Merkel cell carcinoma without sebaceous carcinoma. This is the first report of such co-existent lesions.