[Merkel cell carcinoma of the eyelid. An often unrecognized tumor entity : Clinical aspects and treatment strategies].

Merkel cell carcinoma of the eyelid is an aggressive, highly malignant tumor of the skin. Totaling approximately 0.5 % of all tumors of the eyelid, it constitutes a relatively small group of lid tumors. Nevertheless Merkel cell carcinoma is of significance to the ophthalmologist. Because of its clinical presentation it can be easily confused as a chalazion, a hordeolum or the lesser aggressive basal cell carcinoma. This often leads to delayed treatment. In this article we describe clinical aspects, which aim to help the ophthalmologist suspect Merkel cell carcinoma earlier. Additionally we outline a diagnostic and therapeutic workup taking into consideration the special anatomy of the eyelid.