Dermoscopic Features of Bowen's Disease
The most characteristic dermoscopic features of Bowen's disease (squamous cell carcinoma in situ) are glomerular vessels and a scaly surface, which appear in approximately 90% of cases 1, 2.
Primary Dermoscopic Findings
Non-Pigmented Bowen's Disease
The British Association of Dermatologists guidelines explicitly state that dermoscopy aids diagnosis by showing:
- Glomerular vessels (dotted/coiled vessels)
- Scaling 1
Research confirms these findings are present in 90% of cases, making them highly reliable diagnostic markers 2. The glomerular vessel pattern represents the characteristic vascular architecture visible through dermoscopy that cannot be appreciated with naked eye examination.
Pigmented Bowen's Disease
When pigmentation is present (occurring in 1.67%-5.5% of cases), additional dermoscopic features include:
- Small brown globules regularly packed in patchy distribution (90% of pigmented cases)
- Structureless grey to brown pigmentation (80% of pigmented cases) 2
- Radial rippling of pigment (recently described potential indicator) 3
Clinical Context
Dermoscopy serves as an adjunct to clinical diagnosis but does not replace histopathological confirmation 1. The guidelines emphasize that while dermoscopy can aid diagnosis, a punch biopsy should be performed when:
- Diagnostic doubt exists
- Confirmation is required before treatment
- Full-thickness assessment is needed to exclude invasive disease 1
Differential Diagnosis Pitfalls
The presence of glomerular vessels and scaling is relatively specific, but pigmented variants can mimic:
- Pigmented actinic keratosis
- Seborrheic keratosis
- Solar lentigo
- Atypical nevus
- Melanoma 3
When evaluating multiple lesions on chronically sun-damaged skin, the presence of vessels, ulceration, fiber sign, keratin mass, and blood spots decreases the probability of a lesion being simple actinic keratosis and should prompt biopsy consideration 4.
Practical Application
In routine practice, dermoscopy showing glomerular vessels and scaling in an erythematous hyperkeratotic plaque with irregular borders strongly supports the clinical diagnosis of Bowen's disease 1, 2. However, histopathological confirmation must be obtained prior to treatment to avoid misdiagnosis, particularly given that 3-5% of Bowen's disease progresses to invasive squamous cell carcinoma 5, 6.
The combination of clinical appearance (well-demarcated erythematous hyperkeratotic plaque) plus dermoscopic findings (glomerular vessels and scaling) provides high diagnostic confidence, but biopsy remains the gold standard 1.