A biopsy from lesional skin shows interface dermatitis with a 'saw-tooth' pattern of epidermal hyperplasia, wedge-shaped hypergranulosis, and colloid bodies. The dermal infiltrate is band-like and 'hugs' the epidermis. This pattern is characteristic of:

• A Psoriasis
• B Discoid lupus erythematosus
• C Pityriasis rosea
• D Lichen planus ✓

Explanation

Lichen planus demonstrates characteristic histopathology: irregular acanthosis with a 'saw-tooth' rete ridge pattern, prominent wedge-shaped hypergranulosis, colloid (Civatte) bodies from apoptotic keratinocytes, and a dense lichenoid lymphocytic infiltrate that 'hugs' the DEJ, often obscuring it. DIF shows linear fibrinogen and shaggy IgM at the DEJ. Psoriasis shows Munro microabscesses, suprapapillary thinning and parakeratosis. DLE shows liquefactive degeneration of the basal layer with perifollicular infiltrate.

Reference: Neena Khanna Illustrated Synopsis of Dermatology & STD, 6th ed.

High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP

Written and medically reviewed by the StethoPrep medical team.