SKIN TUMORS
I- Introduction/Generalities:
Skin tumors (skin tumors) are benign or malignant lesions that develop in one of the layers of the skin.
They are common in adults; their progression is generally slow.
II- Anatomical reminder:
The skin is made up of three layers: epidermis – dermis – hypodermis.
The skin covers the entire body and reproduces its external forms.
(surface anatomy).
Its surface area varies depending on the weight and height of the subject (70 kg – 1.70 m: corresponds to a body surface area of 1.80 m2).
Skin color is due to the surface distribution of four main components:
* melanin: brown pigment
* carotene, which varies in color from yellow to orange
* oxyhemoglobin: red
* carboxyhemoglobin: purple
Two superimposed layers, the dermis lined by the epidermis.
The dermis rests on the hypodermis which provides the junction with the subcutaneous anatomical structures.
1 – The dermis
The dermis or chorion is the essential layer of the skin. It gives it its
resistance and elasticity; it is in the dermis that the receptors of the various modes of exteroceptive sensitivity are located.
Its superficial face is bristling with reliefs of varying height, the dermal papillae, which mesh the dermis and epidermis.
The dermis is rich in connective fibers (75% of the structure).
- Collagen: support, extensibility and resistance, very abundant in scarred skin, with an anarchic organization in clusters responsible for hypertrophy.
- Elastin: elasticity of healthy skin, virtually nonexistent in scar tissue.
2 – The epidermis
The epidermis or superficial layer covers the dermis and reproduces the surface of the skin with its projections, depressions and orifices.
It is a keratinized stratified squamous epithelium (five layers) permanently produced by the basal layer.
It is at the dermis-epidermis junction that the melanocytes are found (production of melanin).
3 – The hypodermis
The hypodermis, in its most complete constitution, comprises three superimposed layers:
-The adipose panicle, fatty tissue, divided into lobules by connective tissue trabeculae which are inserted into the deep face of the dermis.
-The fascia superficialis or subcutaneous tissue, which can be isolated by dissection. Its extensions limit the compartments containing the fatty lobules
-The subcutaneous cellular tissue represents a sliding plane of the skin on the underlying superficial fascia.
It is in this layer that the subcutaneous vascular and nerve branches travel.
SKIN TUMORS
Skin constitution
III- Risk factors and precancerous lesions:
A- Sun exposure and pigmentation
A major risk factor, the risk increases with time and intensity
Harmful effects of UVB radiation: premature aging of the skin
B- Precancerous dermatological lesions
- Old scars (burns)
- Chronic ulceration (leg ulcer)
- Actinic keratoses: observed in exposed areas, appear as yellowish or brownish macules of a few mm and cm. Without treatment, they develop into squamous cell carcinoma in 12 to 25% of cases.
C-Toxic and iatrogenic factors
- Polycyclic aromatic hydrocarbons (tars, mineral oils)
- Arsenic: occupational, dietary, medicinal (Fowler’s fluid formerly used in psoriasis)
- Iatrogenic factors:
– PUVA therapy (per-osal psoralen + UVA exposure)
10 years of exposure = risk of squamous cell carcinoma
– Immuno-suppressive therapies: Azathioprine (used in kidney transplant patients)
– Ionizing radiation: radiodermatitis
– HIV+ subject: high risk
D-Genetic predisposition factors:
→Basal cell nevomatosis:
Autosomal dominant syndrome which associates: maxillary cysts , ectopic calcifications, multiple basal cell carcinoma and sometimes other tumors (sarcomas)
→Xeroderma pigmentosumm:
Hereditary condition of autosomal recessive transmission, characterized by:
– Premature skin aging due to photosensitization
– DNA repair deficiency
– Precancerous lesions and carcinoma appear early (8 years)
→Albinism:
Congenital melanin deficiency characterized by increased sensitivity to UV.
SKIN TUMORS
🡺 Vercuciform epidermolysis:
Autosomal recessive transmission, characterized by flat or warty skin lesions of viral origin (Papilloma virus)
IV- Main skin tumors:
1- Benign tumors:
Represented by:
- Papillomas, warts, condylomas
- Noevus (beauty spots)
NB: Any skin lesion that has appeared recently and is changing in size, shape or colour should be examined…BIOPSY+++
2- Malignant tumors:
– Basal cell carcinoma: exclusively cutaneous in location
– Squamous cell carcinoma: located in the skin or mucosa, its local development is aggressive.
– Melanoma: developed at the expense of melanocytes, it appears in the form of a flat black or dark brown spot, aggressive cancer
– Kaposi’s sarcoma: occurs in patients infected with HIV, it is characterized by the development of spots on the skin, mouth, nose, throat, blood vessels, etc.
V- Tumors of the oral cavity:
1/ Lip tumors:
Easily accessible to the eye, they must be detected early. They are developed at the expense of the labial skin, the labial mucosa or the vermilion
| Benign tumors | Precancerous conditions | Malignant tumors |
| -Benign epithelial tumor-Benign connective tissue tumor | -keratotic white lesions-Non-keratotic or slightly keratotic white lesions-melanoma in situ | -Squamous cell carcinoma-Basal cell carcinoma-Glandular carcinoma-Melanoma |
2/Tongue tumors:
- Tongue cancer: to be feared +++
- Seat: movable tongue or base of the tongue
- Most common histological type: squamous cell carcinoma
- Risk factors: tobacco, alcohol, HPV infection.
SKIN TUMORS
3/Gingival tumors:
- Benign: papilloma, hemangioma
- Malignant: squamous cell carcinoma (risk of frequent invasion of the maxillary bone)
VI- Treatment of skin tumors
It is essentially surgical. Surgery allows histological control of the excised specimen.
Surgery for skin tumors ranges from simple outpatient excision-suture to two-stage excision with plastic reconstruction under general anesthesia, depending on the procedure to be performed.
Treatment of malignant tumors may involve radiotherapy (basal cell carcinoma and squamous cell carcinoma) and chemotherapy (inoperable squamous cell carcinoma).
Key points:
- Know how to detect a suspicious skin lesion
- Any budding, ulcerated lesion in the oral cavity requires a biopsy.
- Distinguishing between benign and malignant tumors
Dental crowns are used to restore the shape and function of a damaged tooth.
Bruxism, or teeth grinding, can cause premature wear and often requires wearing a retainer at night.
Dental abscesses are painful infections that require prompt treatment to avoid complications. Gum grafting is a surgical procedure that can treat gum recession. Dentists use composite materials for fillings because they match the natural color of the teeth.
A diet high in sugar increases the risk of developing tooth decay.
Pediatric dental care is essential to establish good hygiene habits from an early age.