Skin nontumor
Lichenoid and interface reaction patterns
Pityriasis lichenoides chronica


Topic Completed: 1 August 2011

Minor changes: 19 March 2020

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PubMed Search: Pityriasis lichenoides chronica [title]

Mowafak Hamodat, M.B.Ch.B., M.Sc.
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Cite this page: Hamodat M. Pityriasis lichenoides chronica. PathologyOutlines.com website. http://www.pathologyoutlines.com/topic/skinnontumorPLC.html. Accessed July 8th, 2020.
Definition / general
  • Presents with red-brown papules with wafer-like scale
  • Overlaps with pityriasis lichenoides et varioliformis acuta
  • Shows predeliction for males in late childhood and early adulthood
  • Involve the arms, legs, trunk and buttocks; flexors are more commonly affected than the extensors
  • Associated with itching and burning sensation
  • Some seasonal variation, worsening in winter and some improvement in sunlight
Case reports
Clinical images

Contributed by Mark R. Wick, M.D.

Arms

Breast skin



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Pityriasis lichenoides chronica

Microscopic (histologic) description
  • Similar to PLEVA, but less destructive
  • Parakeratosis present in well-demarcated zones; vacuolar interface change and lymphocyte exocytosis less than PLEVA
  • Wedge shaped pattern of dermal lymphocytic infiltrate
  • The chronic lesion shows parakeratosis with lymphocytes, similar to Munro microabscesses of psoriasis
  • Purpura is often present
Microscopic (histologic) images

Contributed by Mark R. Wick, M.D.

Breast skin

Positive stains
  • IgM and C3 in the walls of the superficial dermal blood vessels
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