Sebaceous carcinoma of the eyelid with Pagetoid involvement of the bulbar and palpebral conjunctiva.

A case of sebaceous carcinoma with pagetoid involvement of the palpebral and bulbar conjunctival epithelium was studied by light and electron microscopy. Ultrastructurally the neoplastic cells within the conjunctival epithelium were identical to those in the underlying invasive sebaceous carcinoma. Evidence of gradual transformation of conjunctival epithelial cells to the neoplastic sebaceous cells or transitional forms between conjunctival epithelial cells and sebaceous cells was not encountered. The evidence thus supports the theory that the neoplastic cells in the conjunctival epithelium are the result of secondary invasion by the underlying sebaceous carcinoma.