Fine structure of palpebral molluscum contagiosum and its secondary conjunctival lesions.

One case of molluscum contagiosum of the lid, which has been followed by follicular conjunctivitis and superficial punctate keratitis, has enabled us to compare the ultrastructure of the skin tumor and of the conjunctival lesion. Electron microscopic observation is the only way for discovering the causal Poxvirus. Up to now isolation of the viral strain has not been possible. Examination of the skin tumor showed different maturation forms of the virus and associated cell alterations. In the conjunctiva there was an inflammatory reaction, with exocytosis and infiltration of the chorion by lymphocytes and plasma cells. Intracytoplasmic organelles were formed in the superficial epithelial cells. Their size and structure resembled that of the immature virions found in the epidermic cells. The comparison between skin and conjunctival lesions suggests the following sequence of events in the pathogenesis: the virus, leaving the lid tumor, probably penetrates the conjunctival cells and, without finding the conditions necessary for its full development, produces abnormal viral inclusions unable to become a mature virus. The excision of skin nodules thus cures the infection, since it prevents further reinfection by the skin virus. The morphological criteria on which this hypothesis is based must be confirmed by chemical and morphometrical studies.