Pathology

  • Hyperkeratosis, no parakeratosis
  • Wedge-shaped hypergranulosis 🡪 Wickham striae
  • Irregular acanthosis with sawtooth rete ridges
  • Band-like lymphocytic dermal-epidermal junction infiltrate with basal layer vacuolar degeneration and Max-Joseph spaces
  • Melanin incontinence 
  • Colloid bodies in lower epidermis and superficial dermis (stain + for immunoglobulins M, A, G, or C3 on direct immunofluorescence)
  • Shaggy fibrinogen on direct immunofluorescence at dermal-epidermal junction

  • Bullous lesions: subepidermal separation with many eosinophils
  • Papular lesions: normal lichen planus features

  • Perifollicular inflammation (upper half of follicle) at early stage 
  • Follicular destruction at later stage 
  • Immunoglobulins M, G, A + on direct immunofluorescence along the follicular-dermal interface

  • Identical to classic lichen planus findings
  • Pitting of the nail matrix
  • In advanced disease: chromonychia, lamina fragmentation, onycholysis, splinter hemorrhage

  • Parakeratosis
  • Atrophic epidermis

  • Identical to classic lichen planus findings + occasionally eosinophils/plasma cells
  • Focal parakeratosis
  • Colloid bodies in upper epidermis