Bowen's disease
Synonyms and keywords: Bowen's carcinoma; squamous cell carcinoma in situ of skin; intraepidermal carcinoma skin, Intraepithelial neoplasia

# Overview
In medicine (dermatology), Bowen's disease (BD) is a sunlight-induced skin disease, classified either as an early noninvasive stage or intraepidermal form of squamous cell carcinoma which if left undiagnosed, untreated, or neglected has <10% chance of malignant transformation into invasive squamous cell carcinoma of the skin. It usually appears as a erythematous, scaly or crusty patch or plaque anywhere on the body but most commonly involves lower legs, with other possible sites of involvement to be head, neck, genitals, and skin folds. It is easily curable by various treatment options such as cryotherapy, curettage, cautery, photodynamic therapy, topical chemotherapy, radiotherapy, or excision of the lesion.

# Historical Perspective
- In 1912, Dr John T. Bowen was the first one to describe this disease, hence, it is named after him

# Pathophysiology

## Microscopic Pathology
- Cells in Bowen's disease are extremely unusual or atypical under the microscope
- In many cases, cells look worse under the microscope than the cells of many outright and invading squamous cell carcinomas
- Degree of atypia (strangeness, unusualness) seen under the microscope best tells how cells may behave (should they invade another portion of the body)

## Borst-Jadassohn phenomenon
- Bowen's disease can also occur as a part of Borst-Jadassohn phenomenon (previously known as intraepidermal epithelioma) which is a heterogeneous group of following intraepithelial lesions:
Irritated seborrheic keratosis
Clonal seborrheic keratosis
Eccrine poroma
Malignant eccrine poroma
Intraepithelial neoplasia (Bowen's disease)
Other intraepidermal sweat gland tumors
- Irritated seborrheic keratosis
- Clonal seborrheic keratosis
- Eccrine poroma
- Malignant eccrine poroma
- Intraepithelial neoplasia (Bowen's disease)
- Other intraepidermal sweat gland tumors

# Causes
Bowen's disease is a non-infectious, non-familial disease with common causes as mentioned below:
- Solar damage due to long-term sun exposure or use of sunbeds, especially in people with fair skin
- Aging
- Carcinogens such as arsenic:
Used in manufacturing industry and for other commercial uses
10 years or so after  the initial exposure to arsenic are required before it causes Bowen's disease
Well water once used in various medical preparations was known to have been contaminated with arsenic in past
- Used in manufacturing industry and for other commercial uses
- 10 years or so after  the initial exposure to arsenic are required before it causes Bowen's disease
- Well water once used in various medical preparations was known to have been contaminated with arsenic in past
- Weak immune system due to:
Immunosuppressants after organ transplant
AIDS
- Immunosuppressants after organ transplant
- AIDS
- Viral infection such as:
Different types HPV/human papillomavirus:
HPV 16, 18, 34, and 48 are associated with Bowen's disease of perianal & genital region especially bowenoid papulosis and VIN are caused by HPV 16
HPV 2, 16, 34, and 35 are associated with Bowen's disease in other areas of body (excluding genitals)
47% of acral and 24% of nonacral extragenital Bowen's disease lesion contains HPV genome
Merkel cell polyomavirus
- Different types HPV/human papillomavirus:
HPV 16, 18, 34, and 48 are associated with Bowen's disease of perianal & genital region especially bowenoid papulosis and VIN are caused by HPV 16
HPV 2, 16, 34, and 35 are associated with Bowen's disease in other areas of body (excluding genitals)
47% of acral and 24% of nonacral extragenital Bowen's disease lesion contains HPV genome
- HPV 16, 18, 34, and 48 are associated with Bowen's disease of perianal & genital region especially bowenoid papulosis and VIN are caused by HPV 16
- HPV 2, 16, 34, and 35 are associated with Bowen's disease in other areas of body (excluding genitals)
- 47% of acral and 24% of nonacral extragenital Bowen's disease lesion contains HPV genome
- Merkel cell polyomavirus
- Previous irradiation such as:
Ultraviolet irradiation
Radiotherapy treatment
Photochemotherapy
- Ultraviolet irradiation
- Radiotherapy treatment
- Photochemotherapy
- Chronic skin injury
- Dermatoses
- Sjogren's syndrome

# Epidemiology and Demographics

## Age
- Bowen's disease can affect adults of any age, most commonly involves older patients in their 60s or 70s
- It is rare before the age of 30 years

## Gender
- Bowen's disease occurs more predominantly in men than in women (70-85% of cases)

## Race
- Caucasians are the ones most commonly affected by Bowen's disease

# Natural History, Complications and Prognosis
- Bowen's disease grows very slowly over the period of months or even years
- It is easily treatable if diagnosed in time
- If left undiagnosed, untreated or neglected, Bowen's disease can ultimately progressively develop into invasive squamous cell carcinoma of the skin in 1 in 20-30 people (i.e. 3-5% risk)
- SCC is a treatable condition, but if it's deeper  or invasive, it means it's very serious

# Diagnosis

## Common symptoms
- It usually appears as one or more skin patches with following characteristics:
Persistent
Progressive
Non-elevated
Non-healing
Irregular clear edges
Scaly
Crusty
Red or pink
Warty (verrucous)
Upto a few centimetres across (larger than half-inch wide)
Flat or raised
Oozing of pus
Itchy (but not all the time)
Splits open (fissured)
Darkly colored (pigmented)
- Persistent
- Progressive
- Non-elevated
- Non-healing
- Irregular clear edges
- Scaly
- Crusty
- Red or pink
- Warty (verrucous)
- Upto a few centimetres across (larger than half-inch wide)
- Flat or raised
- Oozing of pus
- Itchy (but not all the time)
- Splits open (fissured)
- Darkly colored (pigmented)

## Signs and symptoms of malignant transformation
- Following changes in the skin patch are the signs that bowen's disease has turned into invasive squamous cell carcinoma of the skin:
Easy bleeding
Tenderness
Turns into an open sore i.e. ulcerates
Hardening (induration)
Develops into a lump/fleshy nodule
- Easy bleeding
- Tenderness
- Turns into an open sore i.e. ulcerates
- Hardening (induration)
- Develops into a lump/fleshy nodule

## Common sites of involvement
- Common sites involved are:

### Skin
- Lesions can occur anywhere on the skin surface or on mucosal surfaces, although the involvement of palms or soles is uncommon
- A persistent progressive non-elevated red scaly or crusted plaque which is due to an intradermal carcinoma and is potentially malignant
- Atypical squamous (resembling fish scales) cells proliferate through the whole thickness of the epidermis

### Extremities
- About three-quarters of the patients have lesions on the lower leg (60-85%), usually in previously or presently sun-exposed areas of skin

### Head and neck area
- Being prone to the sun exposure, head and neck area is also one of the common sites to be affected by Bowen's disease

### Subungal, periungal region
- Bowen's disease also commonly involves subungal or periungal areas (i.e. either under or around fingernails or toenails)

### Skinfolds

### Genitourinary system
- Bowen's disease can also involve genital and perianal areas
- It appears in following 3 forms in genital area:

## Physical Examination
- Bowen's disease typically presents as a gradually enlarging, well demarcated erythematous plaque with an irregular border and surface crusting or scaling
- Lesion might feel tender representing its malignant transformation

## Dermoscopy
- Dermoscopy is the skin examination via skin surface microscopy
- Also known as:
'Epiluminoscopy'
'Epiluminescent microscopy'
- 'Epiluminoscopy'
- 'Epiluminescent microscopy'
- It is usually used for examination of pigmented skin lesions
- Benefits of dermoscopy include:
Improvement of diagnostic accuracy of pigmented skin lesions
Evaluation of nonpigmented skin tumors (recognizes vascular structures not visible to naked eye)
Helpful in diagnosis of Bowen's disease and shows:
Repetitive morphological findings such as glomerular vessels and scaly surface
Small brown globules and/or homogeneous pigmentation in case of pigmented Bowen's disease
- Improvement of diagnostic accuracy of pigmented skin lesions
- Evaluation of nonpigmented skin tumors (recognizes vascular structures not visible to naked eye)
- Helpful in diagnosis of Bowen's disease and shows:
Repetitive morphological findings such as glomerular vessels and scaly surface
Small brown globules and/or homogeneous pigmentation in case of pigmented Bowen's disease
- Repetitive morphological findings such as glomerular vessels and scaly surface
- Small brown globules and/or homogeneous pigmentation in case of pigmented Bowen's disease

## Skin biopsy
- Skin biopsy must be done to:
Confirm the diagnosis Bowen's disease
Differentiate from other skin lesions
Rule out invasive squamous cell carcinoma of the skin
- Confirm the diagnosis Bowen's disease
- Differentiate from other skin lesions
- Rule out invasive squamous cell carcinoma of the skin

# Treatment
- Specific treatment for an individual case depends upon various factors, such as:
Affected body site
Size
Thickness of the lesion(s)
Number of the lesion(s)
Presence or absence of certain symptoms
Patients age
Patient's general health
Possible side effects of the treatment
Possible long term effects of the treatment
Patient's preference
- Affected body site
- Size
- Thickness of the lesion(s)
- Number of the lesion(s)
- Presence or absence of certain symptoms
- Patients age
- Patient's general health
- Possible side effects of the treatment
- Possible long term effects of the treatment
- Patient's preference
- Different treatment options for Bowen's disease include the following:

# Prevention
Following are the few preventive measures to lower the risk for developing Bowen's disease:

# Differentiating Bowen's disease from other Diseases
- Bowen's disease must be differentiated from the following:
Psoriasis
Eczema
Superficial basal cell carcinoma
Actinic keratosis
Seborrheic keratosis
Lichen planus
Tinea corporis
Extramammary Pagets disease
- Psoriasis
- Eczema
- Superficial basal cell carcinoma
- Actinic keratosis
- Seborrheic keratosis
- Lichen planus
- Tinea corporis
- Extramammary Pagets disease