A 55-year-old postmenopausal woman presents with a 2-year history of intense vulvar pruritus and dyspareunia. Examination reveals ivory-white atrophic plaques with characteristic cigarette-paper wrinkling distributed in a figure-of-eight pattern encircling the vulva and anus. Telangiectasias and purpura from minor trauma are noted. The structure marked **B** in the diagram is suspected. Which of the following best describes the pathogenic mechanism underlying this condition?
A. Estrogen deficiency causing vaginal atrophy with loss of normal flora
B. HPV-driven epithelial dysplasia with keratinocyte hyperproliferation
C. T-cell mediated autoimmune response with genetic susceptibility (HLA-DQ7) and possible Borrelia burgdorferi involvement
D. Immune complex deposition in the basement membrane zone with linear IgA deposition
Explanation
Why T-cell mediated autoimmune response is right
The condition marked B (lichen sclerosus) is a chronic inflammatory dermatosis with a well-established autoimmune pathogenesis. The clinical presentation—ivory-white atrophic plaques with cigarette-paper wrinkling, figure-of-eight distribution, telangiectasias, and purpura from fragile vessels—combined with the bimodal age distribution (postmenopausal women and pre-pubertal girls) is pathognomonic for LS. The underlying mechanism involves T-cell mediated inflammation, genetic susceptibility to HLA-DQ7, and controversial associations with Borrelia burgdorferi (particularly in European populations). Histologically, this manifests as a lichenoid lymphocytic infiltrate with basal vacuolar degeneration and a characteristic homogenized pink zone of hyalinized collagen in the upper dermis (BAD Guidelines 2018).
Why each distractor is wrong
Estrogen deficiency causing vaginal atrophy: This describes atrophic vaginitis, which occurs in postmenopausal women but lacks the characteristic atrophy, wrinkling, figure-of-eight distribution, purpura, and intense pruritus of LS. Atrophic vaginitis is not associated with architectural distortion or malignant transformation.
HPV-driven epithelial dysplasia: While LS carries a 4–6% lifetime risk of vulvar squamous cell carcinoma (differentiated-type VIN), this is an HPV-independent pathway. The primary pathogenesis is autoimmune, not HPV-driven; HPV involvement is a complication, not the cause.
Immune complex deposition with linear IgA: This pattern describes cicatricial pemphigoid or linear IgA disease, which present with blistering and scarring but lack the characteristic ivory-white plaques, wrinkling, and figure-of-eight distribution of LS. Direct immunofluorescence would be negative in LS.
High-YieldNEET PG
Lichen sclerosus = autoimmune (T-cell), not hormonal; bimodal age distribution (postmenopausal women + pre-pubertal girls); figure-of-eight vulvoanal distribution; ivory-white atrophic plaques with cigarette-paper wrinkling; 4–6% SCC risk requiring lifelong surveillance.
BAD Guidelines for Lichen Sclerosus 2018; AAD Position Statement 2024
Practice similar questions
Sign up free to access AI-powered MCQ practice with detailed explanations and adaptive learning.
