How can I differentiate Bowen's disease from other skin lesions during a clinical examination?

Bowen's disease is a form of squamous cell carcinoma in situ that presents clinically as a persistent, well-demarcated, erythematous, scaly patch or plaque on the skin. During clinical examination, it can be differentiated from other skin lesions by its characteristic features: a slowly enlarging, irregularly bordered, reddish or brownish lesion with a scaly or crusted surface, often resembling eczema or psoriasis but not responding to usual treatments.

Unlike basal cell carcinoma, which typically presents as pearly or waxy nodules with rolled edges and prominent fine blood vessels, Bowen's disease lacks nodularity and ulceration. It also differs from invasive squamous cell carcinoma, which may show ulceration or a more nodular appearance. Melanoma lesions are usually pigmented and can be assessed using the weighted 7-point checklist, whereas Bowen's disease is non-pigmented or lightly pigmented and scaly.

Clinical suspicion of Bowen's disease should be raised when a non-healing, scaly erythematous patch persists, especially in sun-exposed areas, and does not improve with standard topical treatments. Dermoscopy may aid in differentiation but biopsy remains essential for definitive diagnosis and to exclude invasive carcinoma.

Early recognition is important as Bowen's disease represents squamous cell carcinoma in situ and can progress to invasive squamous cell carcinoma if untreated (Scurtu et al., 2024). Referral pathways should be considered if there is suspicion of progression or diagnostic uncertainty, following the suspected cancer referral guidelines for skin lesions suspicious of squamous cell carcinoma ¹.