A retrospective study of skin biopsies of 184 cutaneous lichen planus patients

Background: Lichen planus (LP) is a chronic inflammatory and immune-mediated disease characterized by multiple clinical presentations. There are very few studies analyzing histopathological features of LP worldwide. Objectives: The aim of this work was to study different histopathological patterns in skin biopsies of LP and to correlate the clinical and histopathological features. Materials and Methods: Records of 184 biopsies diagnosed as LP were included in the study. Clinical data from the records reviewed. Hematoxylin and eosin-stained sections were retrieved, re-examined, and histopathological parameters were noted. Results: Among the 184 biopsies of LP patients, pigment incontinence (93.5%) was the most common followed by hypergranulosis (88%) and interface dermatitis (82.6%). In epidermal changes, saw-toothed acanthosis (90, 48.9%) was the most common followed by the flattened epidermis (47, 25.5%), irregular moderate acanthosis with appendageal involvement (31, 16.9%), and pseudocarcinomatous hyperplasia (16, 8.7%). In tissue reaction patterns, the lichenoid pattern was the most common (131, 71.2%) followed by mild superficial perivascular dermatitis (MSPVD) in 20 (10.9%) followed by various combination patterns. The types of hypergranulosis seen were wedge-shaped (86, 53.1%) followed by infundibular (32, 19.8%), regular (30, 18.5%), and acrosyringeal (14, 8.6%). Changes of venous stasis were observed in 41% of lower limb biopsies. Conclusion: On histopathology, pigment incontinence and hypergranulosis were the most consistent features in all types of LP. Awareness about the less frequent patterns may improve the diagnostic accuracy of clinicopathologic correlation.