Sean Klepper M.D.
Stephen Lyle, M.D., ...
Also known as: lichen planus-like keratosis, solitary lichen planus
- Most common in middle aged white individuals, with a female predominance
- Usually of short duration
- Most often presents as a solitary, sharply demarcated papule or plaque, with a predilection, for the face, neck, upper trunk and distal upper extremity
- Often misdiagnosed clinically as a seborrheic wart, superficial BCC or acitinic keratosis
- The findings are quite similar to those of lichen planus:
- Hyperkeratosis, often with focal parakeratosis
- Variable acanthosis
- Basal cell vacuolar change
- Often exocytosis of lymphocytes
- Epidermal and dermal colloid bodies
- Pigment incontinence
- The saw-tooth rete ridge pattern typically of lichen planus is sometimes seen, but lichenoid keratosis more frequently shows broadened, irregular rete ridges.
- There is most often a dense lichenoid lymphohistiocytic infiltrate, as in lichen planus; however, occasionally the infiltrate in lichenoid keratosis is mainly perivascular. Focal plasma cells and eosinophils may also be present.
- The basal layer may show reactive atypia.
- Immunofluorescence shows staining for IgM and sometimes IgG, as in lichen planus.