RESUMEN
Merkel cell carcinoma is a rare cutaneous carcinoma, featured by an aggressive clinical course and a mortality rate of 28% at 2 years. A 71-year-old female was affected by a 4.1-cm-wide locally advanced Merkel cell carcinoma of the upper eyelid, previously misdiagnosed as chalazion, with involvement of the extraocular muscles. Although the tumor showed a macroscopic spontaneous regression in size after the incisional biopsy, the mass was treated with neoadjuvant chemotherapy and surgical excision. Good functional and aesthetic result with preservation of the eyeball and absence of tumor recurrence were achieved at 3-year follow-up. In our experience, the combination of the inflammatory cascade due to the incisional biopsy and neoadjuvant chemotherapy led to the regression of a locally advanced large Merkel cell carcinoma of the eyelid.