title: Histopathological features of molluscum contagiosum other than molluscum bodies.
abstract: OBJECTIVE
  Classic histopathological features of molluscum contagiosum (MC) include a crateriform, acanthotic epidermis containing intracytoplasmic molluscum bodies (MBs). In our experience, a subset of cases lack these features on initial haematoxylin and eosin-stained sections. We aimed to describe the histopathological features of MC other than those classically described.
  
  
  RESULTS
  Sixty-seven biopsies diagnosed as MC from January 2011 to October 2012 were retrospectively reviewed. Keratinocytes peripheral to the diagnostic cells with MBs had prominent nucleoli (67; 100%), amphophilic cytoplasm (54; 81%), and in many instances clear cytoplasmic vacuolization (38; 57%). Stroma surrounding MC lesions showed fibroedematous to fibromyxoid changes in many cases (36; 54%), with a subset (13; 19%) showing abundant dermal mucin. In eight of 67 cases (12%), initial sections did not possess MBs or crateriform epidermis of MC. In these cases, initial sections revealed only the epithelial and/or perilesional stromal changes described above. Additional sections contained MBs in all of these cases.
  
  
  CONCLUSIONS
  Perilesional fibroedematous to fibromyxoid stroma and keratinocyte changes, including prominent nucleoli and amphophilic cytoplasm with clear vacuolization, are common in MC. Recognizing these features may prove helpful in reaching the diagnosis of MC in cases lacking classic histopathological features on initial sections.
authors.affiliation: Department of Pathology, University of Michigan, Ann Arbor, MI, USA.
authors.forename: Martin K
authors.initials: MK
authors.lastname: Ishikawa
authors.affiliation: Department of Pathology, University of Michigan, Ann Arbor, MI, USA.
authors.forename: David P
authors.initials: DP
authors.lastname: Arps
authors.affiliation: Department of Dermatology, University of Michigan, Ann Arbor, MI, USA.
authors.forename: Conroy
authors.initials: C
authors.lastname: Chow
authors.affiliation: Department of Pathology, University of Michigan, Ann Arbor, MI, USA.
authors.forename: Thomas L
authors.initials: TL
authors.lastname: Hocker
authors.affiliation: Department of Pathology, University of Michigan, Ann Arbor, MI, USA.|Department of Dermatology, University of Michigan, Ann Arbor, MI, USA.
authors.forename: Douglas R
authors.initials: DR
authors.lastname: Fullen
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001706:Biopsy; D002648:Child; D002675:Child, Preschool; D005260:Female; D006801:Humans; D007223:Infant; D015603:Keratinocytes / Q000473:pathology*; D008297:Male; D008875:Middle Aged; D008976:Molluscum Contagiosum / Q000473:pathology*; D012867:Skin / Q000473:pathology*; D055815:Young Adult
keywords: dermal mucin; fibroedematous stroma; fibromyxoid stroma; molluscum contagiosum; papular mucinosis; viral dermatoses