Abstract:

This transcript provides a detailed histopathological analysis of a shave biopsy, ultimately diagnosing Hypertrophic Lichen Planus. The examination begins by identifying marked, patchy epidermal acanthosis and dense orthokeratosis. A crucial contextual clue is the presence of dilated dermal blood vessels (stasis change), indicating the biopsy likely originates from the lower leg, consistent with the patient's presentation of itchy shin plaques. Microscopic review at the dermo-epidermal junction reveals a dense, band-like lichenoid infiltrate of lymphocytes, actively destroying the basal layer and forming vacuoles and Civatte bodies – hallmarks of lichenoid interface dermatitis. The video emphasizes key features differentiating hypertrophic lichen planus from its classic form, including its typical lower leg location, characteristic "skipping" acanthosis, and the presence of eosinophils and plasma cells in the infiltrate. Finally, it notes that hypertrophic lichen planus can clinically mimic basal or squamous cell carcinomas.

Summarizing a Shave Biopsy: Hypertrophic Lichen Planus

• 0:00:02 Low Magnification Biopsy Features: A broad shave biopsy shows areas of markedly thickened epidermis (acanthosis) interspersed with normal areas. The surface is covered with dense, compact orthokeratin, with some scattered parakeratosis.
• 0:00:37 Clinical Location Clues (Stasis Change): The presence of dilated blood vessels (stasis change) in the papillary dermis is a key indicator that the biopsy is from the lower leg (shin), correlating with the patient's complaint of very itchy plaques on the anterior shins. This is a common, age-related finding due to gravity.
• 0:01:37 Dermal-Epidermal Junction Infiltrate: At the base of the acanthotic epidermal regions, there is a dense, band-like infiltrate of lymphocytes, characteristic of a "lichenoid infiltrate," which is actively damaging the basal layer.
• 0:02:18 Signs of Interface Dermatitis: The lymphocytic attack on the basal layer leads to the formation of small bubbles (vacuolar change or liquefactive degeneration) and pink blobs (Civatte bodies or dying keratinocytes), blurring the normal distinction between the dermis and epidermis, which is the definition of an interface change.
• 0:03:03 Diagnosis: Hypertrophic Lichen Planus: Based on the clinical presentation (itchy plaques on lower legs) and the histopathological findings (acanthosis, orthokeratosis, lichenoid interface dermatitis with vacuolar change and Civatte bodies), the diagnosis is hypertrophic lichen planus.
• 0:03:20 Distinguishing Features of Hypertrophic Lichen Planus: This variant typically occurs on the lower legs and is characterized by "skipping" areas of acanthosis (alternating thick and normal epidermis), with the interface change most prominent at the tips of the elongated rete ridges. Unlike regular lichen planus, it often includes eosinophils and plasma cells within the inflammatory infiltrate.
• 0:04:09 Clinical Mimicry: Hypertrophic lichen planus can sometimes present as solitary lesions that clinically resemble basal cell carcinoma or squamous cell carcinoma, necessitating biopsy for accurate diagnosis.