Epidermal Naevus
It has different names, such as linear epidermal naevus or verrucous naevus. These are hamartomas originating from the epidermal layer of the skin. Clinically they form keratotic and pigmented papules and even papillomatous plaques.
Clinical Forms of Epidermal Naevus
They are often located on the head and neck. They are located along the body lines described by Blaschko. They are often asymptomatic, meaning that apart from their appearance they cause the person no discomfort. They are located along the Blaschko lines of our body shown in the picture below. They may occur in a localised area or in a systematised form.
Systematised epidermal naevus, i.e. naevus that is widespread on the body, is called "Solomon syndrome". In this clinical form there are wart-like papules arranged along a line, but instead of a single lesion there are many lesions. On the trunk, the lines of distribution, which usually run in parallel, may be found on only one side of the patient or may show a bilateral and symmetrical distribution. Systematised epidermal naevus may be accompanied by skeletal and muscular deformities, eye disorders, central nervous system diseases such as intellectual disability, epilepsy and sensorineural deafness, and diseases of the heart and genitourinary organs.
The localised form is mostly present at birth, with a lesion along a line made up of raised, wart-like papules arranged side by side. Because the tumour, which can be located on the head, trunk or limbs, is on only one side of the patient, it is often called "naevus unius lateris".
A variant of localised linear epidermal naevus is described as "naevus comedonicus"; it is a tumour made up of papules arranged along a line, each with a dark, hard plug in its centre resembling the comedones in acne. Naevus comedonicus can also be located on the palms and soles, as well as other areas.
The development of epidermoid skin cancers on linear epidermal naevi is known, as is the development of BCC in cases on the scalp associated with "naevus sebaceus and syringocystadenoma papilliferum".
A special form of epidermal naevus is "inflammatory linear verrucous epidermal naevus (ILVEN)". Here the lesions are more inflamed, even resembling psoriasis plaques, and are common in childhood, especially in girls. The clinical signs are again linear and seen on the legs. Itching is prominent, and it is important to differentiate it from psoriasis.
Treatment of Epidermal Naevus
Epidermal naevi are often asymptomatic and benign. Patients' treatment goals are entirely cosmetic.
In epidermal naevi, treatments are chosen taking into account factors such as the patient's age and the location, extent and pigment level of the lesions. Many treatment methods are used for this purpose.
- Topical or intralesional cortisone
- Other topical drugs such as calcipotriol, 5-fluorouracil, podophyllin, retinoids and chemical peels
- Cryotherapy, dermabrasion, electrosurgery, curettage, surgical procedures and laser treatments are other treatment options.
- Photodynamic therapy is also preferred.
- They are treated with methods such as tretinoin, electrodesiccation and curettage, cryotherapy, laser and surgical excision.
Naevus Verrucosus
It appears at birth or shortly afterwards. These are skin-coloured or brown, slightly raised, wart-like lesions seen mostly on the face, scalp, neck, thorax and limbs. The lesion can take various forms, from a small plaque on the scalp to lesions merging with each other in a linear arrangement on different parts of the body. Basal cell carcinoma can develop on these lesions. The most definitive treatment is total excision.
Ichthyosis Hystrix
This term has been used to describe a number of different, rare, severe disorders of keratinisation characterised by massive hyperkeratosis. The term has also sometimes been used to describe localised and linear wart-like epidermal naevi associated with intellectual disability, seizures or skeletal anomalies. A few extremely rare syndromes can be classified as true forms of ichthyosis hystrix:
ICHTHYOSIS HYSTRIX GRAVIOR – LAMBERT TYPE: a condition characterised by hyperkeratosis covering the whole body except the face, genitals, palms and soles. It was first described in the Lambert family in England at the beginning of the 18th century.
ICHTHYOSIS HYSTRIX GRAVIOR – CURTH-MACKLIN TYPE: a disorder characterised by porcupine-like changes and keratoses on the palms and soles. The histological findings differ from those of all other ichthyoses.
ICHTHYOSIS HYSTRIX GRAVIOR – RHEYDT TYPE: a condition characterised by keratoses on the limbs, particularly including the flexural surfaces, and to a lesser extent on the face and ears. In these patients, alopecia and hair and nail abnormalities have been seen in addition to sensorineural deafness.
In ICHTHYOSIS HYSTRIX GRAVIOR – BAEFVERSTEDT TYPE, only isolated cases have been described to date.
Epidermal Naevus Syndrome
Epidermal naevus syndromes represent a group of different diseases that can be distinguished by the type of associated epidermal naevus and whether or not they are heritable. Well-defined syndromes characterised by organoid epidermal naevi include Schimmelpenning syndrome, phacomatosis pigmentokeratotica, naevus comedonicus syndrome, angora hair naevus syndrome and Becker naevus syndrome. The molecular basis of these diseases has not been determined to date. In contrast, the group of syndromes characterised by keratinocytic naevi consists of 3 phenotypes with a known molecular aetiology: CHILD syndrome (congenital hemidysplasia with ichthyosiform naevus and limb defects), type 2 segmental Cowden disease and fibroblast growth factor receptor 3 epidermal naevus syndrome (Garcia-Hafner-Happle syndrome); nevertheless, the origin of Proteus syndrome is still unknown. From this overview, it is clear that a specific type of these diseases cannot be classified under the name "epidermal naevus syndrome" or under the terms "organoid naevus syndrome" or "keratinocytic naevus syndrome".
ILVEN
ILVEN is a term formed from the initial letters of the words inflammatory linear verrucous epidermal naevus. ILVEN is a type of epidermal naevus. An epidermal naevus is a skin condition present from birth that develops as a result of overgrowth of the epidermal (upper) layer of the skin.
The disease develops as a result of a disorder, in the period before birth, of the layer we call the ectoderm, which forms nerve tissue and the epidermis. As a result of this anomaly, a number of anomalies may also develop in the skeletal system, eyes and brain. However, this is quite rare.
ILVEN consists of wart-like lesions that form groups and show a linear distribution. Unlike other epidermal naevi, ILVEN involves redness and itching. The surface of the skin may be eczema-like (dry, red, itchy) or psoriasis-like (red and scaly).
The disease usually affects one leg and can also spread to the buttocks and foot. It can be seen at birth, but usually appears in the 5th year of life and spreads and enlarges over the months and years. The disease is more common in girls.
There is no definitive cure for the disease. Moisturisers and low-potency cortisone creams can reduce itching.
Naevus Sebaceus
These are benign skin tumours most often located on the scalp, followed by the forehead and behind the ears. They are usually solitary and cause the patient no complaints. They are mostly present at birth. They occur equally in men and women.
In "Jadassohn syndrome", a very rare form, there is linear sebaceous naevus, fainting attacks and intellectual disability. In addition, naevus sebaceus may be accompanied by eye, skeletal system and vascular anomalies.
The lesions vary from oval to linear in shape. Their diameter ranges from 0.5 cm to 7 cm. When located on the scalp, there is no hair on them. Their surface is flat or slightly indented. In adulthood they become raised on the skin and take on a more tumour-like structure.
In later life, benign or malignant tumours can develop on them, especially around the age of 40. For this reason, early diagnosis and preventive surgery should be carried out.
Becker Naevus
Becker naevus appears as a large brown patch on one side of the body, sometimes covering half of the chest and upper back. After puberty it becomes darker and hairy. Sometimes acne develops on it.
"Melanocytes", the cells that give the skin its colour, play an important role in skin colouring by producing "melanin", a pigment. Among the cells lining the base of the uppermost layer of the skin (the epidermis), one in every 5–10 cells is a melanocyte.
The cells of "naevi", popularly known as "MOLES", are also cells thought to differentiate from melanocytes and are capable of synthesising melanin. These cells tend to form cell clusters. The common feature of both cell types is their potential to transform into "malignant melanoma (= black cancer)", the only true cancer of the pigment-producing cells of the skin.
These coloured, tumour-like formations of the skin, which are generally harmless and mostly consist of moles, are usually brown or black. Some are raised above the skin, while others are at skin level. They can be observed in very variable sizes. They can be congenital or appear later. They are given different names according to their appearance, colour, location or the cells from which they originate.
Becker naevus sometimes appears or increases under the influence of sunlight. Similarly, it may be observed that with age their number increases, their colour darkens or lightens and they become larger. Increased hair growth on them may be seen with age.
Their colour varies between light brown and skin colour, and sometimes they can be black. The number and size of lesions may increase with age. They can be confused with other similar diseases common especially in old age, or with some conditions involving changes in skin colour. They cause no complaints and can be removed only with treatments planned for cosmetic purposes. Patients with such signs should be advised about sun protection.
Very rarely, as with other birthmarks, there may be some disorders in the underlying tissues formed from the same embryonic cell type, the ectoderm. This condition is known as Becker naevus syndrome. In this syndrome there are anomalies such as smooth muscle hamartoma (overgrowth of the smooth muscle beneath the naevus), underdevelopment of the underlying breast, pectoral muscle, fatty tissue, arms, chest wall and spine, and overgrowth of the adrenal gland, arms, legs, fingers, toes and scrotum.
There is no definitive treatment for Becker naevus. However, if the affected area is protected from the sun, it remains less noticeable.
Excess hair on the naevus can be reduced with laser treatment. The brown colour can also be reduced with pigment lasers, but this is generally not effective or may make the patch more noticeable.
When Becker naevus is accompanied by acne, classic acne treatment is given; in severe cases the drug isotretinoin is used.
Seborrhoeic Keratosis
Although seborrhoeic keratoses are often confused with warts, they are quite different from warts. Seborrhoeic keratosis is a non-cancerous growth of the upper part of the skin. There may be one, or they may occur in groups. Although they are usually brown, they can vary from light brown to black. Their size can vary greatly. Their surface looks waxy. Sometimes they look as if brown wax has dripped onto the skin.
What causes seborrhoeic keratosis?
The real cause of seborrhoeic keratosis is unknown. However, anyone can have a few of these growths. They become more common with advancing age. Some people develop many seborrhoeic keratoses over time, while others develop fewer. Seborrhoeic keratoses may be seen during pregnancy, in those receiving oestrogen therapy, or together with certain medical problems.
Where do they occur?
Although seborrhoeic keratosis can be seen on the scalp, face, neck and anywhere on the body, they are most often found on the chest and back. They are less common below the waist. As the sun does not affect the appearance of seborrhoeic keratoses, they can also be seen in areas not exposed to the sun. When they first appear, they are small bumps with a rough surface. Later they thicken and take on a wart-like surface.
Can anyone have seborrhoeic keratosis?
They are rarely seen in children. Although new ones may appear around seborrhoeic keratoses, they are not contagious. They are seen somewhat more often with advancing age.
Is seborrhoeic keratosis important?
Anyone can have a few of these growths. Although they appear suddenly, seborrhoeic keratosis is not a sign of serious disease and has no connection with skin cancer.
Especially on the face, they may not be raised above the skin. Friction from clothing can irritate seborrhoeic keratoses. Over the years, seborrhoeic keratoses may grow, itch, become irritated and bleed. In this case they need to be treated. Seborrhoeic keratoses may turn black, in which case it can be difficult to distinguish them from skin cancers. In this case the seborrhoeic keratosis should be surgically removed and examined under the microscope to distinguish it from cancer.
Can seborrhoeic keratosis be prevented?
Ointments and medications do not provide a complete cure and do not prevent seborrhoeic keratosis.
How are they treated?
Most seborrhoeic keratoses are treated with one of 3 methods. The first method is cryosurgery, or freezing. A very cold liquefied gas called liquid nitrogen is applied to the seborrhoeic keratosis. A blister forms beneath the seborrhoeic keratosis, which dries to form a crust. Within a few weeks the keratosis falls off. No scar remains when it heals. Occasionally a small white or dark mark may remain.
Another method is known as curettage. These growths are scraped off with the help of a curette. After the area is numbed with an injection or spray, the seborrhoeic keratosis is removed from the skin. No stitches are needed and bleeding is minimal and can easily be stopped by applying pressure. Electrosurgery is another treatment method. The skin is first numbed, then an electric current is applied and the lesion is scraped off.
Naevoid Hyperkeratosis of the Nipple
Naevoid hyperkeratosis of the nipple and areola is a benign condition of unknown aetiology. It can affect the nipple, the areola or both. The distribution is usually bilateral, sometimes unilateral. Although it can affect both sexes, about 80% of cases are women. Clinically, the typical lesion in naevoid hyperkeratosis of the nipple consists of verrucous thickening and dark pigmentation of the nipple and areola.
Naevus Comedonicus
Naevus comedonicus is a rare adnexal hamartoma variant of unknown cause. It usually appears as grouped follicular openings containing keratin plugs on the face, neck and trunk. The literature reports that naevus comedonicus may be accompanied by many diseases, such as developmental anomalies of the eyes, skeletal system, central nervous system and other parts of the skin. When naevus comedonicus is accompanied by neurological anomalies such as cerebrovascular malformation, cortical atrophy, hydrocephalus, intracranial calcification and dysgenesis of the corpus callosum, it is called "naevus comedonicus syndrome". This very rare syndrome is classified among the epidermal naevus syndromes.