3.3.2 Carcinoma in situ

 2E64

Bowen’s disease (skin), erythroplasia of Queyrat (glans penis), leukoplakia (mucous epithelia).

Incidence 15/100,000/year in persons with white skin. 

Carcinoma in situ (intraepidermal and intraepithelial carcinoma).

UV exposure, immunosuppression, HPV, tobacco, betel nut.

Circumscribed erythematous (sometimes scaly) patch or plaque, persistent whitish mucosal lesions.

Sun-exposed skin, genitalia, buccal mucosa.

Grade 1 to 3 according to progression and involvement by histology.

None 

Dermoscopy can be of great help diagnosing this entity. Vessels can form irregular clusters of coiled vessels and/or globular vessels (small red clods). A scaly surface and pigmented structures may be seen arranged in lines as well as white circles may be present, often in irregular clusters. There may be superficial erosion and crusting.

Using polarisation, white shiny ‘crystalline’ structures may form rosettes on facial skin.

Orthohyperkeratosis (pink) alternating with parakeratosis (blue). Abnormal keratinocytes. Pseudopod-like proliferation of the epidermis. Solar elastosis in the upper dermis. 

Lesions gradually enlarge in an irregular fashion. The surface may become hyperkeratotic or crusting. Field cancerisation may finally develop.

Transition to invasive cutaneous or mucosal squamous cell carcinoma.

Diagnosis relies on clinical picture and histology. 

Depending on localisation (lips, buccal or genital mucosa): superficial basal cell carcinoma, bowenoid papulosis, extramammary Paget’s disease. Confirmation by histology.

Depends on localisation and histological type. For example: excision, cryosurgery, photodynamic therapy, radiotherapy, 5-fluorouracil or imiquimod cream.

None.