What is the most suitable investigation for diagnosing cutaneous (skin) Bowen disease?

Most Suitable Investigation for Cutaneous Bowen Disease

The most suitable investigation for cutaneous Bowen disease (squamous cell carcinoma in situ) is histopathological examination showing hyperkeratosis, parakeratosis, and acanthosis. 1

Diagnostic Approach to Bowen Disease

Primary Diagnostic Method

Histopathology is the gold standard for diagnosing Bowen disease. The typical histopathological features include:

• Full-thickness epidermal dysplasia
• Hyperkeratosis (thickening of the stratum corneum)
• Parakeratosis (retention of nuclei in the stratum corneum)
• Acanthosis (thickening of the epidermis)

These features are essential for confirming the diagnosis and differentiating it from other skin conditions 1, 2.

Obtaining Tissue for Histopathology

• A punch biopsy is preferred over curette biopsy as it allows examination of the full thickness of the epidermis and dermis 1
• This is crucial to establish whether there is any invasive disease that would indicate progression to squamous cell carcinoma

Adjunctive Diagnostic Methods

While histopathology remains the gold standard, other investigations can support the diagnosis:

1. Dermoscopy findings:

   • Glomerular vessels (69.2% of cases)
   • Scaly surface (78.8% of cases)
   • Yellow crusts (56.8% of cases)
   • Focal hemorrhage (55.5% of cases) 3

2. Immunohistochemistry markers:

   • p53 positivity in tumor cells
   • High molecular weight cytokeratin expression
   • HPV markers (especially in genital lesions) 2

Clinical Presentation and Diagnosis

Bowen disease typically presents as a well-demarcated, erythematous hyperkeratotic plaque with an irregular border 1. The diagnosis is often made on clinical grounds, but histopathological confirmation is essential due to:

• Morphological similarity to other cutaneous disorders 4
• Risk of progression to invasive squamous cell carcinoma (3-5% for typical Bowen disease) 1
• Need to rule out invasive disease before selecting treatment

Pitfalls and Caveats

1. Diagnostic challenges:

   • Bowen disease can mimic common dermatological conditions, leading to misdiagnosis 5
   • Persistent cutaneous lesions of uncertain diagnosis or "steroid-nonresponsive" dermatitis should prompt consideration of Bowen disease 4

2. Sampling issues:

   • Inadequate biopsy depth may miss invasive components
   • Multiple biopsies may be needed for large or heterogeneous lesions

3. Special situations:

   • Pigmented variants may be confused with melanocytic lesions
   • Genital Bowen disease (erythroplasia of Queyrat) has higher risk of invasion (approximately 10%) 1

Algorithm for Diagnosis

1. Clinical suspicion based on persistent, well-demarcated erythematous plaque
2. Dermoscopic examination (looking for glomerular vessels and scaling)
3. Punch biopsy for histopathological confirmation
4. Histopathological assessment for hyperkeratosis, parakeratosis, and acanthosis
5. If diagnosis remains uncertain, consider immunohistochemistry for p53 and cytokeratin markers

By following this approach, accurate diagnosis can be achieved, allowing for appropriate treatment selection and reducing the risk of progression to invasive squamous cell carcinoma.