Phakomatous choristoma of the eyelid.

This article describes the first report of phakomatous choristoma of the eyelid in Korea. A six-month-old boy underwent excision of a congenital inferonasal orbital mass arising from the left lower lid. A dermoid cyst was suspected, however a diagnosis of phakomatous choristoma was made following conventional histology. An immunohistochemical study of this rare benign congenital tumor was conducted. The cuboidal epithelial cells comprising this choristoma showed strongly positive cytoplasmic staining with S-100 protein and vimentin. They also showed focally positive staining with a neuron-specific enolase, while they showed no immunoreactivity to cytokeratin or epithelial membrane antigen. The results of the immunohistochemical study support the conclusion that this tumor is of lenticular anlage origin.