title: Demonstration of a unique viral structure: the molluscum viral colony sac.
abstract: Using scanning electron microscopy to study molluscum contagiosum lesions, it has been possible to demonstrate a unique, well defined sac enclosing the virion colony of each infected keratinocyte. This confirms the presence of a structure demonstrated over 50 years ago by micro-dissection, but ignored since it is not seen on either light or transmission electron microscopy. It is postulated that this sac, of unknown origin, favours replication of the virions by providing a site that is both anatomically and immunologically privileged. Such relatively unimpeded growth of the virions results in an enlarged cell in which the cytoplasm and nucleus are compressed into a thin outer shell. In the aggregate, this produces a tumour of virus-packed cells rather than a tumour composed of virus-induced cell hyperplasia.
mesh_terms: D000293:Adolescent; D000328:Adult; D002648:Child; D002675:Child, Preschool; D000078404:Epidermal Cells; D004817:Epidermis / Q000648:ultrastructure; D006801:Humans; D007633:Keratins; D008854:Microscopy, Electron; D008855:Microscopy, Electron, Scanning; D008976:Molluscum Contagiosum / Q000473:pathology*; D008977:Molluscum contagiosum virus / Q000648:ultrastructure*; D012867:Skin / Q000648:ultrastructure*; D014771:Virion / Q000648:ultrastructure*
chemical_list: D007633:Keratins