skin cancer


Introduction / Classification :

  • Skin cancers are common, observed in subjects with light skin type variable incidence worldwide : d & rsquo peaks; incidence recorded among American and Australian whites
  • The primary cutaneous cancers include 2 main groups :

Cancers epithelial : derived from keratinocyte, or squamous cell carcinoma : basal cell carcinoma and squamous

Cancers  Non-epithelial :  drift d & rsquo; other cells : melanoma (melanocyte), sarcomes (fibroblaste)

  • Epithelial skin cancers are the most common.
  • Cutaneous melanoma is less common but terrible prognosis ; c & rsquo; is the largest provider deaths

tumorsGenesis :

  • Various alterations occur on skin cell (keratinocyte, melanocyte, other cells) will lead to the cancer cell
  • Cell transformation is the fact of genetic events inducing irreversible genomic abnormalities disrupting cell proliferation

Agents exogenous : cause alterations in the & rsquo; cellular DNA, it s & rsquo; follows a mutation leading to cancer cell : Ultraviolet A or B, ionizing radiation or oncogenic viruses

Agent chemical : polycyclic aromatic hydrocarbons, pesticides

  • Genès and cancers cutaneous :

Genoa officials from the transformation cellular : abnormal, only in tumor cells, specific carcinogenic factors, ultraviolet +++

Genoa giving a predisposition genetic at cancer : geno-dermatosis exposure to risk skin tumor development, mainly Xeroderma pigmentosum, mutations are carried by all cells of the body. early age

Genoa suppressor from tumors (gene P53) : control proper cell cycle progression, it is a true guardian of the genome, cell cycle arrest after genotoxic stress (UV), which can repair genomic damage before continuing mitosis

  • Tumorigenèse through fault from repair of the alterations cell : l & rsquo; normal individual possesses an enzymatic equipment capable of repairing the preceding alterations, however, during certain genetic diseases that enzymatic equipment is faulty or missing (Xeroderma pigmentosum). L & rsquo; when normal individual & rsquo; he sees advancing age s & rsquo; weaken its repair means of cellular alterations (peak incidence in the elderly)
  • Absence d & rsquo; elimination of the cell abnormal : to & rsquo; normal, the antitumor immune system ensures the & rsquo; removing any abnormal cells. The severe immune deficiencies will allow the & rsquo; emergence of tumor clones

Carcinoma basal cell

skin cancer 2Fromfinish :

  • Malignant epithelial tumor from keratinocyte
  • More common in patients with a history of clear phenotype & rsquo; intense sun exposure.
  • strict skin cancer, occurs immediately on healthy skin
  • photo-exposed areas, never touch the mucous membranes
  • prognosis (never metastasis)
  • The invasive potential is purely local (malignancy +++ locale)
  • surgical treatment

Épidémiologie :

  • The most common epithelial cancers, alone represents 70% epithelial cancer.
  • High incidence in countries with high insolation (Australia +++)
  • elderly, > 40 years, clear phenotype history of & rsquo; intense sun exposure
  • factors from risk :

Soleil : major carcinogenic factor, Repeated sun exposure (vacation, sports activity) -> prevention and school education measures

skin cancer 3Predisposition genetic : are more frequent in subjects with clear skin, phototype I/II

MC1R  :  gene involved in skin pigmentation (photo-protective melanin),  some variants are risk factors for skin cancer

Géno-dermatoses predispose to the carcinomas basal cell : Xeroderma pigmentosum

Immunodépression : Organ transplant recipients are more basal cell carcinomas, VIH

Aspects clinics :

  • Lesion elementary : small papule of the color of the transparent normal skin (translucent), suggesting the vessels in the dermis- Underlying as telangiectasias, This lesion is called "epitheliomatous pearl"

Seat : sun-exposed areas, in 80% cases : head, cou, face

  • shapes clinics :

Form nodular : the elementary lesion can remain unique and increase in size giving a colored nodule dew covered by fine telangiectasias, The most common form

Plan scar : the elementary injury multiplies, epitheliomatous several beads are s & rsquo; arranging rosary and take a rounded arrangement :   smooth atrophic center and periphery elevated by the juxtaposition of beads

Carcinoma  basal cell  tattooed :  the elementary lesion will be pigmented, brown spots, covering the surface of the tumor melanoma nodular ≠

Form sclerodermiform : white plate, hard and shiny vague limits, the surface is depressed and retractile, traveled telangiectasia. Recidivism +++

Form  ulcerated  (ulcus rodens)  :  ulceration coup d & rsquo; nail, d & rsquo; slow expansion, whose edge is beaded

Form Drilled : ulceration burrowing with a large necrotic crater that can lead to severe mutilation

Diagnostic :

  • Diagnostic positive :

Clinique : before the fixity of injuries, the beaded edge and the presence of telangiectasia

histology : a proliferation of small basaloid cells with clear limits recalling the cells of the epidermal basal layer. These cells are grouped into clusters and compact mobile device take a provision palisade. The tumor remains well delimited from the rest of the dermis

  • Diagnostic differential : squamous cell carcinoma, malignant melanoma (in pigmented forms)

ISevolution / Prognosis :

  • Spring, exceptional metastases
  • Basal cell carcinoma is essentially local evolution

Form ulcerated : destruction of the subcutaneous tissue, cartilage tissue or bone tissue underlying creating a gate & rsquo; entry to secondary infection germs and complicating d & rsquo; nasosinusal infection or septic source of mortality meningitis

Traitement :

  • Surgery : treatment of choice, allows histological control of margins & rsquo; excision : complete surgical resection + regular monitoring for recurrence
  • Other arms therapeutic : if topography at risk and / or multiple lesions or subject to risk : radiotherapy, Cryotherapy in & rsquo; liquid nitrogen, PDT

Prévention :

Uses effective photoprotection c & rsquo; is to say, :

  • Clothing : wearing clothing covering, hat
  • use of the screens solar : allows less photoprotection, it requires repeated applications & rsquo; d & rsquo sunscreens; high index

Carcinoma spinocellulaire

skin cancer 4Fromfinish :

  • Malignant epithelial tumor, primitive d & rsquo; origin keratinocyte, squamous cell carcinoma
  • From new  or precursor (precancerous lesion),  skin and mucous membranes
  • Extending both local, locoregional and distance
  • 2e frequency keratinocyte carcinomas, 20% skin cancer epithelial.
  • O & rsquo; observed in the subject of & rsquo; age, after 60 years of clear skin type and living in sunny areas

Épidémiologie :

  • Man > women, age > 60 years
  • Very high incidence in Australia, the incidence increases with age
  • occurrence of the risk of squamous cell carcinoma is linked to 2 factors : cumulative dose of sun exposure, phototype

skin cancer 5factors etiological (precancerous lesions)

  • precursors of the carcinomas squamous cutaneous :

Kératose   actinic :  frequent lesion on image areas- exposed : face, extremities, scalp. Old person, clear skin, erythematous lesion, brownish, rough

Kératose radiation-induced

Kératose     of the     hydrocarbons    polycyclics     aromatics : incomplete combustion of wood, coal or oil (refining products, fuels, tar…)

scarring   skin :   burns,   radiodermites -> regular monitoring +++

wounds chronic : Chronic Leg Ulcers -> risk of degeneration

  • precursors of the carcinomas squamous of the mucous :

Lips :

Chéilite actinic chronic : professionals in the sun : atrophy, erosion, squames, bottom lip +++

Chéilite smoking : smoking, keratosis plate, whitish

mucous anogénitale :

Origin infectious :

HPV   :   types oncogènes,   Bowen's disease, carcinomas in situ

Dermatose mucous :

Lichen sclerotic : chronic dermatosis, pruritus +++, vulva, whitish lesion, sclerosis

CLinique :

  • beginning : squamous cell carcinoma, often develops over a precancerous lesion :  actinic keratosis,  Bowen's disease,  scar burns, radiodermatitides, chronic ulceration. The formed lesion associated 3 components : budding, ulceration, infiltration

Form  ulcerative vegetating  :  commonest,  protruding and invasive tumor, uneven surface, Seat budding ulceration and saignotant, indurated edges

  • Seat of the injury : uncovered areas (head, cou), upper and lower limbs, mucosal and submucosal half : language, lips, vulva and glans

shapes clinics :

The tumor associated in proportions varying different semiotic elements :

  • Form ulcerative vegetating : the most common
  • Form ulcerated pure
  • Form vegetating : cauliflower, easy bleeding
  • Form nodular : nodular lesion protruding, warty and scabby

Diagnostic positive :

Clinique + histology

  • Squamous cell carcinoma should be suspected in the presence of any precancerous lesion, appearance of a crust, d & rsquo; a budding, bleeding, d & rsquo; a skin induration, d & rsquo; an underlying infiltration. The presence of & rsquo; one of these signs must impose to do a skin biopsy to confirm the diagnosis
  • histology : cell proliferation large sizes with many atypical mitosis and cyto-nuclear, these cells are grouped into lobules or ill-defined bays, there is a keratinizing differentiation as horny globes, the underlying dermis is often invaded

Evolution / Prognosis :

  • potentially invasive cancer, local extension step by step
  • Exam clinique : search & rsquo; lymphadenopathy in & rsquo; lymphatic drainage air because the tumor lymph node metastases are early. Before any sign of & rsquo; call, of diagnostic tests will be carried out in search of blood-borne metastasis, liver and lung

Traitement :

  • excision surgical : full up & rsquo; to & rsquo; hypoderme -> small tumor and prognosis.

➢ If topography aesthetic risk and / or functional -> cryochirurgie, radiotherapy, laser…

➢ In case of metastases : surgery, palliative treatment

Prévention :

  • solar photoprotection.
  • Treatment of any precancerous lesion.
  • Screening and surveillance of high-risk individuals.