BENIGN SKIN TUMOR
Benign tumor: grows by expansion without invasion of the extra-cellular matrix .Malignant tumor(cancer):grows by invasion into the extra-cellular matrix.Cysts Epidermal cyst (Epidermoid cyst; Sebaceous cyst)- The most common form of cyst form.- It contains keratin and its breakdown products, surrounded by a wall of stratified squamous keratinizing epithelium.- The origin is pilosebaceous apparatus.- Can occur in any age group, It may inherited as an autosomal dominant form. - Common sites are face, neck, shoulder and chest. - It may be single or multiple(inherited type). - Fixed to the skin, with punctum. - It enlarges in size slowly reaching up to 1-5cm diameter.
- Complications as;i- simple inflammation increase in size and become tender.ii- Infection results in abscess formation.iii- Ulceration leads to lesion called Cock’s peculiar tumor peculiar, the differential diagnosis is squamous cell carcinoma.iv- Rupture and leak of content outside, forms what is called sebaceous horn OR leak in surrounding to the surrounding tissue and cause local inflammation.Treatment by excision, through an Elliptical excision of overlying skin and enucleation of the cyst. Incomplete excision of wall results in recurrence. Treatment of infected cyst is incision and drainage not excision.
Pillar cystSimilar to epidermal cyst but without punctum, common site is scalp. Usually multiple, solitary in 30% cases. It may inherited as autosomal dominant.
Dermoid cystsare subcutaneous cysts that form along lines of embryologic fusion. Commonly, Dermoid cysts are congenital and occur on the head, around the eyes. Histologically, they are lined by epidermis and appendages. Treatment is surgical excision, preoperative radiological investigation is needed to exclude intracranial extension.
Millia1-2mm papules that are white, superficial, firm lesions. They are superficial epidermal cysts, commonly occur on the face.
Pigmented lesions :
benign pigmented naevi(mole) result when melanocytes increased in numbers in the layers of skin, presented as:- Lentigo, which are present within the basal layer of the epidermis.- Junctional naevi, which occur as localized aggregation projecting into the dermis.- Dermal naevi, which occur entirely within the dermis. - Compound naevi, which show the features of both the Junctional and dermal naevi.- one ore more naevi present in more than 95% of white adults.- can appear at any site of the body even the nail bed and conjunctiva.- usually appear during childhood and adolescence, increase in size gradually with age. They are not pre-malignant lesions.
Epidermal tumors
Keratoacanthoma: common cutaneous benign tumor, common age is elderly men above 6th decade. Common site is sun-exposed areas. The clinical is rapid, in three phases; rapid growth for 4-8 weeks, latent period for another 8 weeks, then regression phase. It appears as well circumscribed with firm, round borders and an umbilicated keratotic center. Treatment is excision.Seborrheic keratoses: are common, benign keratoses seen on the trunk and face, appear after the 4th decade and are brown, hyperpigmented, verrucous papules measuring from 3mm to more than several centimeters. They are not premalignant lesions.Callosities: are thickened or hardened parts of skin. They are commonly occur on pressure or friction areas like the hand and feet, so they may be occupational.Corn: is a horny induration of the cuticle with a hard center, caused by undue pressure, chiefly affecting the toes and feet. Wart: is a dry , rough excrescence on the skin. It is a virus-induced tumor that undergoes spontaneous resolution.
Connective tissue tumor
Dermatofibroma: is a firm, single or multiple nodule. It may follow minor trauma or insect bites. It occur on both sexes, at any age group, and common sites are extremities. They often itch, vary in size and are frequently pigmented. treatment is excision of symptomatic lesion.Lipomas: are dermal or subcutaneous collection of adipose tissue. Most lesions are solitary, discrete nodules that remain asymptomatic and occur over the trunk and extremities. Some patients may have an autosomal dominant inherited condition of multiple lipomatosis. Surgical excision is the treatmant of choice.Leiomyomas: are typically painful papules that may occur on the trunk. Lesions are typically erythematous papules of less than 6mm.Xanthomas: Hyperlipoproteinemias are associated with cutaneous Xanthomas. They are of different types; eruptive(buttocks and extensor surfaces), tuberous(elbow, knee, fingers, and buttocks),
xanthelasma(eyelids), according to the type of Hyperlipoproteinemia. Laboratory investigations are needed before treatment. Treatment include systemic treatment of Hyperlipoproteinemia and surgical excision if needed.
Neurofibroma: are benign soft tumor of fibrous and nerve tissue elements. It appears a soft, lobulated mass with irregular surface and margin. It is of three types;- Single Neurofibroma.- Plexi-form Neurofibroma: affecting wide area of skin which appears as large masses, common sites are face and upper limbs.- Multiple neurofibramatosis(Von-Recklinghausen’s syndrome): is a hereditary disorder (autosomal dominant) manifested by multiple cutaneous Neurofibromas, café au lait pigmentation and axillary freckling. It is associated with bony, intracranial lesions and gastrointestinal symptoms. 10% of cases have Pheochromocytoma and malignant hypertension. Treatment, after diagnosis by clinical examination an biopsy, is genetic counseling and reassurance. Surgical treatment as excision or debulking may be used for large masses.
Premalignant tumors
Actinic keratoses(Solar keratoses, senile keratoses):are areas of epidermal dysplasia giving rise to cutaneous scaling, usually observed in sun-exposed fair skin. These are premalignant lesions of squamous cell carcinoma. Treatment includes local diathermy, cryosurgery, laser, local chemotherapy as 5-flourouracil, and surgical excision.Bowen’s disease: is an intraepidermal squamous cell carcinoma that is potentially malignant and appears as a persistent, progressive, usually flat, red, scaly or crusted, plaque. It is more frequently seen in the elderly. Treatment is same as actinic keratoses
Erythroplasia of Querat: is Bowen’s disease of the glans penis. It occurs most commonly in uncircumcised males. Radiodermatitis: this an area of skin damaged by
Radiodermatitis: this an area of skin damaged by excessive exposure to X- irradiation. Early erythema occurs which goes on to desquamation and pigmentation. If the dose is very great ulceration may occur. Later atrophy, irregular hyperpigmentation, telangectasia and hair loss occur. Eventually, squamous cell carcinoma may develop.Chronic scar: Marjolin’s ulcer is a carcinoma(SCC) develop in a scar.