Merkel cell carcinoma of the eyelid.

The clinical and pathological features of two Merkel cell carcinomas of the eyelid skin are reported. Both tumours occurred in the upper lid in elderly women and enlarged rapidly to form smooth, round nodules which projected from the lid surface anterior to the grey line. In one case the primary excision biopsy was followed by a wider excision in 1982, and the patient has been free from recurrence or metastases in the intervening period. In the second more recent case, the tumour was inadequately excised in 1984 and the lid was treated by radiotherapy: this patient is at present free from recurrence. Histological examination of each tumour revealed an identical morphology - characterised by the presence of uniform polyhedral cells with multiple nucleoli lying in nests and lobules within the dermis: mitotic figures were prominent. Immunohistochemical studies showed the cells to react positively with antisera against neurone-specific enolase, epithelial membrane antigen and met-enkephalin. Electron microscopy revealed only rare neuroendocrine granules in one tumour, and numerous granules in the other. Intranuclear rodlets were not identified and there was paucity of cell membrane attachment modifications.