Multiple Hypertrophic Lichen Planus Mimicking Squamous Cell Carcinoma: A Case Report.

INTRODUCTION

Hypertrophic lichen planus (HLP) with pseudoepitheliomatous hyperplasia (PEH) can closely mimic well-differentiated squamous cell carcinoma (SCC), creating a clinically important diagnostic pitfall. Fewer than 26 case reports in the literature describe HLP initially misdiagnosed as SCC, underscoring the need for careful clinicopathologic correlation.

CASE PRESENTATION: A 77-year-old woman developed multiple hyperkeratotic nodules and plaques on both legs and feet over 4 months. A punch biopsy led to an initial diagnosis of well-differentiated SCC. An additional elliptical incisional biopsy from a separate plaque showed irregular acanthosis with hypergranulosis, endophytic well-differentiated squamous epithelium, and a dense lichenoid interface infiltrate with focal basal vacuolar change and Max-Joseph spaces, without destructive invasion or significant atypia - findings consistent with HLP with PEH. The lesions flattened with topical clobetasol propionate under occlusion for 6 weeks, and no recurrence was observed during a 3-month follow-up.

CONCLUSION

HLP can closely mimic well-differentiated SCC, making adequate tissue sampling and clinicopathologic correlation essential to avoid unnecessary surgery. This case adds to the limited literature on HLP misdiagnosed as SCC and highlights the need to also consider inflammatory mimickers.