Distinction Between Hypertrophic Lichen Planus and Squamous Cell Carcinoma Requires Clinicopathologic Correlation in Difficult Cases

Hypertrophic Lichen Planus: An Up-to-Date Review and Differential Diagnosis

CONTEXT.—

Hypertrophic lichen planus (HLP) is a variant of lichen planus that can be difficult to diagnose based on histopathologic features alone. Thus, patient clinical history and clinicopathologic correlation are essential considerations to make the correct diagnosis.

OBJECTIVE.—

To discuss the clinical and histologic presentation of HLP and provide a thorough review of commonly encountered mimickers in the differential diagnosis.

DATA SOURCES.—

Data were derived from a literature review, personal clinical and research experiences, and a review of cases in the archives of a tertiary care referral center.

CONCLUSIONS.—

In general, HLP involves the lower extremities and is characterized by thickened, scaly nodules and plaques that are often pruritic and chronic in nature. HLP affects both males and females and is most common in adults 50 to 75 years of age. Unlike conventional lichen planus, HLP tends to have eosinophils and classically displays a lymphocytic infiltrate most concentrated around the tips of rete ridges. The differential diagnosis for HLP is broad and encompasses numerous entities in many different categories, including premalignant and malignant neoplasms, reactive squamoproliferative tumors, benign epidermal neoplasms, connective tissue disease, autoimmune bullous disease, infection, and drug-related reactions. Therefore, a high index of suspicion must be maintained to avoid a misdiagnosis and potential inappropriate treatments.

Case report: Hypertrophic lichen planus initially misdiagnosed as squamous cell carcinoma

Fewer than 26 case reports describe hypertrophic lichen planus (HLP) misdiagnosed as cutaneous squamous cell carcinoma (cSCC). It can be difficult to distinguish between HLP and cSCC, as these two conditions share many clinical and histopathological characteristics. Patients who are misdiagnosed with cSCC often undergo unnecessary medical and/or surgical interventions before receiving a diagnosis of HLP and improving on HLP-directed therapy. This case series highlights the course of three female patients, referred to a single tertiary institution between 2018 and 2022, who were initially misdiagnosed with cSCC before receiving a diagnosis of HLP. We have emphasized the clinical and histopathological distinguishing features between HLP and cSCC, the pathogenesis of HLP, and current and new HLP-directed therapy. We hope that this case series serves as a reminder to dermatologists, dermatologic surgeons, and dermatopathologists to be aware of this diagnostic challenge.

Concomitant hypertrophic lichen planus and squamous cell carcinoma: Clinical features and treatment outcomes

BACKGROUND

Patients with hypertrophic lichen planus (HLP) and squamous cell carcinoma (SCC) diagnoses present clinicians with diagnostic and disease management challenges.

OBJECTIVE

To better define the clinical and treatment outcomes of patients with concomitant diagnoses of HLP and SCC.

METHODS AND MATERIALS

A retrospective review was performed from January 1, 2008, to July 31, 2015, at Mayo Clinic. Patients with a histologic diagnosis of HLP and SCC were included. Patient demographics, associated comorbidities, histopathologic characteristics, treatment, and outcomes were evaluated.

RESULTS

Thirty-three patients were identified; 79% were female, and mostly the lower extremities were involved. Most of the SCCs were well-differentiated and in situ with the majority treated with destruction or excision. There were no cases of local recurrence, metastasis, or disease-specific death during the follow-up period (mean 55.8 months).

CONCLUSION

Patients with diagnoses of both HLP and SCC appear to be a distinct population that is predominantly female with lesion predilection for the lower extremities. However, regardless of treatment modality or tumor size, there were no adverse outcomes. An initial trial of more conservative treatment measures with close follow-up may be reasonable with biopsy of lesions unresponsive to conventional treatment.