Histopathologic Comparison Between Morphea, Lichen Sclerosus, and Systemic Sclerosis: A Prospective Cross-Sectional...

Morphea, lichen sclerosus (LS), and systemic sclerosis (SSc) are chronic sclerosing dermatoses with overlapping clinical features that can complicate diagnosis. Although histopathology is essential for differentiation, comparative studies on their histopathologic characteristics remain limited. This study aimed to compare the histopathologic features of morphea, LS, and SSc, and assess their association with disease duration and clinical induration. Ninety cases (30 each of morphea, LS, and SSc) meeting the inclusion criteria were enrolled. Participants underwent comprehensive clinical evaluation, laboratory investigations, and masked histopathologic analysis. Clinical induration was graded on a 1-3 scale. Significant differences were observed across epidermal, dermal, and subcutaneous features. Epidermal alterations included hyperkeratosis, hypergranulosis, irregular acanthosis, pigmentation, lymphocytic exocytosis, vacuolar interface dermatitis, and subepidermal split (all false discovery rate [FDR] P = 0.001). Dermal and subcutaneous distinctions included sclerosis depth, dermal edema, lymphocytic infiltration, subcutaneous inflammation, increased collagen deposition, and lipomembranous panniculitis (all FDR P = 0.001). Distinctive histologic signs further aided differentiation. Diagnostic performance analysis of histopathologic features revealed several key parameters that reliably differentiate the 3 entities. No histopathologic features were significantly associated with disease duration after FDR correction. Lymphocytic exocytosis was strongly negatively correlated with induration grade (Somer D = -0.632), while hypocellular dermis (Somer D = 0.598) and sclerosis depth (ρ = 0.591) showed positive correlations. This study elucidates distinct histopathologic features that discriminate morphea, LS, and SSc, underscoring the critical importance of a methodical histopathologic evaluation. The correlation between histologic findings and clinical induration emphasizes its pivotal role in both diagnosis and guiding treatment decisions.