What is Epidermal Nevus Syndromes?
Epidermal Nevus Syndrome (ENS) is a term that was initially introduced to describe the combination of skin growths, known as epidermal nevi, and other related features. Over the years, the term has evolved to include more precisely identified skin and nerve-related conditions linked with epidermal nevi. Recent advancements have helped in understanding the genetic causes of many of these conditions, but we are still learning about how certain genes lead to specific physical characteristics, a concept referred to as “genotype-phenotype correlation.”
Common types of epidermal nevi include non-epidermolytic keratinocyte nevus, sebaceous nevus, comedonic nevus, Becker’s nevus, and CHILD nevus (which stands for Congenital Hemidysplasia with Ichthyosiform nevus and Limb Defects). These are all a type of an abnormal skin growth called a hamartoma, falling into two major categories: organoid or keratinocytic.
The conditions that fall under the ENS umbrella term do cause some disagreement in the medical community. Still, some of the most commonly recognized are Schimmelpenning syndrome, Phacomatosis Pigmentokeratotica, Nevus Comedonicus Syndrome, and Becker Nevus Syndrome, usually linked with organoid epidermal nevi. Similarly, Proteus Syndrome and CHILD Syndrome are often related to keratinocytic nevi.
What Causes Epidermal Nevus Syndromes?
In the past decade, we’ve learned a lot about the most common skin conditions known as epidermal nevus syndromes.
One of the most well-known of these is Schimmelpenning syndrome. It was first identified in 1957 and is characterized by a specific type of skin growth known as a nevus sebaceus, often appearing in a streaked or swirled pattern. This condition can be accompanied by issues related to the bones, nervous system, and eyes, such as skull and facial defects, limb deformities, learning difficulties, seizures, brain structure abnormalities, and eye malformations.
Phakomatosis pigmentokeratotica is another condition known for having a nevus sebaceus, but it also involves a second type of skin growth, a papular nevus spilus. This condition is notable because strange patterns can appear that only develop into bumps years later. Like Schimmelpenning syndrome, neurological issues are also seen in individuals with this condition. An interesting fact is that these individuals have a higher likelihood of developing a type of rickets, a disease that softens and weakens the bones.
Nevus comedonicus syndrome involves a nevus comedonicus, a type of skin abnormality, along with issues related to the eyes and nervous system. Some of these issues are cataracts, smaller than normal head size, brain malformations, and seizures. Usually, these findings occur on the same side as the nevus comedonicus.
Becker nevus syndrome is characterized by a skin growth that is associated with physical deformities on the same side of the body. Common issues include underdeveloped breasts, spinal curvature, vertebral defects, and underdeveloped upper body muscles. The skin growth does not typically follow the streaked or swirled pattern seen in other syndromes.
Proteus syndrome is a condition where the bones and connective tissues grow unevenly, causing limbs grow at different rates. This condition also has a specific skin growth found often on the soles of the feet. Affected individuals may display lumps under the skin, patchy thinning of the skin, and fatty lumps (lipomas). A key feature of this syndrome is the neurological issues caused by uneven and disproportionate growth of the bones.
The CHILD syndrome is known for skin growths and is an inherited condition that mostly affects females. This syndrome is characterized by underdevelopment of one side of the body. Symptoms include one-sided limb underdevelopment, paralysis of one side of the face, and underdevelopment of various body systems. The skin growths are well-defined, stop abruptly in the middle of the body, and tend to improve with age. A unique bone finding, stippled calcification of the growth plate, can be spotted early in infancy helping in the diagnosis of the condition.
Risk Factors and Frequency for Epidermal Nevus Syndromes
Epidermal nevus syndromes are a group of rare conditions, with most of the available information coming from individual case reports and collectives of cases. Currently, there is not enough data to accurately describe how common these conditions are. However, in the case of CHILD syndrome, it is observed more frequently in females due to its inheritance pattern, which is linked to the X chromosome.
Signs and Symptoms of Epidermal Nevus Syndromes
Keratinocytic epidermal nevi are skin marks that look like pink to dark-coloured lines or swirls and can become warty over time. They can appear on one or both sides of the body and are usually found on the trunk and limbs. However, they generally stop at the middle of the body.
Sebaceous nevus, on the other hand, is often found on the head and neck. These skin marks are pale salmon or yellow in colour and have a waxy look. They’re also linked to hair loss in the area where they appear. Although typically noticeable at birth, they become more pronounced around puberty because of hormonal changes.
Nevus comedonicus are skin marks characterized by groups of hair follicles filled with keratin, a protein found in the skin. Like acne, these skin marks can also be infested with bacteria and become inflamed.
Becker’s nevi usually appear on the upper trunk or shoulder. They look like light brown patches and can grow more hair, especially around puberty.
CHILD nevus has a unique feature where waxy yellow plaques appear on one side of the body and sometimes follow the lines of skin cell development. Like keratinocytic epidermal nevi, these plaques can also become warty over time.
Testing for Epidermal Nevus Syndromes
If you or a loved one is suspected to have an ENS or Epidermal Nevus Syndrome, which includes a wide variety of skin and other health issues, a team of medical experts is necessary to handle the case effectively. This process usually starts by gathering a full medical history, considering factors from before birth to the present, along with looking into your family’s health history.
A skin specialist who is well-informed about the many types of ENS should conduct a thorough examination of your body, including the soft linings of your body such as the mouth. It’s also essential for a thorough children’s doctor to assess your overall bone health with help from medical imaging or expert opinions from bone and hormone specialists, especially if the patient has bone disease symptoms like rickets.
Routinely checking the brain with imaging is not a normal part of the process unless there’s reason to believe the person might have developmental concerns highlighted in their full medical history. Smaller symptoms on the skin, epidermal nevi, are usually just minor findings not requiring more testing.
However, if these skin features are large, placed on the face or have associated neurological symptoms like seizures, additional imaging may be necessary to ensure there are no underlying brain structural issues. If there’s a potential for neurological involvement, a neurology specialist would need to evaluate the patient. You may also be referred to a genetic specialist who can identify the specific genetic cause of the syndrome and provide advice on the chance of it happening in future generations.
Treatment Options for Epidermal Nevus Syndromes
Typically, only the symptoms that affect parts of the body outside the skin need treatment in conditions known as epidermal nevus syndromes. This can include things such as managing seizures or using orthotic devices to correct differences in leg lengths.
Sometimes, surgery can be used to remove symptom-causing or unsightly skin growths, also known as epidermal nevi. However, in children, it’s not standard to fully remove a specific type of skin growth called a nevus sebaceus. If the nevus sebaceus is causing cosmetic concerns, it can be removed when the child is older and it’s easier to administer local anesthesia. In children, the chances that a nevus sebaceus will become cancerous are quite low.
There are other non-surgical treatments available, such as photodynamic therapy (a treatment that uses a drug, along with a certain kind of light, to kill cells), laser ablation (using laser heat to remove abnormal tissues), and dermabrasion (a skin-resurfacing procedure). These treatments need to be considered on an individual basis. Although they may help to reduce, they can’t completely eliminate the chance of the skin growth becoming cancerous.
The treatment for a specific type of epidermal nevus syndrome, known as CHILD nevus, is unique. It involves a pathway that’s important in the making of cholesterol. Using a topical combination of lovastatin (a drug used to lower cholesterol) and cholesterol has been reported to clear up the skin condition.
What else can Epidermal Nevus Syndromes be?
Schimmelpenning Syndrome is a term that can refer to several different diseases. These conditions include:
- Phacomatosis pigmentokeratotica
- Nevus comedonicus syndrome
- Proteus syndrome
Phacomatosis Pigmentokeratotica is another name for conditions such as:
- Schimmelpenning syndrome
- Proteus syndrome
In the case of Nevus Comedonicus Syndrome, this could also mean:
- Syndrome of segmentally arranged basaloid follicular hamartomas with ipsilateral osseous, dental, and cerebral anomalies
- Munro’s acne nevus
Becker Nevus Syndrome can alternatively be referred to as:
- Giant congenital nevus
- Café au lait macule
Proteus Syndrome is another term for diseases like:
- Klippel-Trenaunay syndrome
- Hyperplasia with lipomatosis
- CLOVES syndrome, which stands for congenital lipomatous overgrowth, vascular malformations, epidermal nevi, and scoliosis/skeletal/spinal anomalies
Finally, CHILD Syndrome can mean:
- Inflammatory verrucous epidermal nevus
- Harlequin change of the newborn
What to expect with Epidermal Nevus Syndromes
The outlook for each of the skin growth syndromes, commonly known as epidermal nevus syndromes (ENS), depends on the extent of involvement outside of the skin. Neurological symptoms, or problems with the brain and nerves, can be life-changing. On the other hand, isolated skin growths, which are epidermal nevi that do not have any other significant outcomes, are typically a cosmetic issue with a low risk of turning into cancer. There’s a noticeable association of various cancers outside of the skin with ENS. Hence, medical screening recommendations are rapidly changing and should be made on an individual basis, evaluated by a genetic specialist.
Possible Complications When Diagnosed with Epidermal Nevus Syndromes
The emergence of cancerous growths like basal cell carcinoma within a nevus sebaceus is a known potential complication, but it happens in less than 1% of these lesions. Other non-cancerous overgrowths probably happen more frequently. If there is any skin growth within this type of blemish that seems questionable, a skin biopsy should be done. An expert in the study of skin diseases should interpret this biopsy to prevent needless invasive procedures. Additionally, screenings for other cancers outside of the skin should be based on symptoms and risk factors.
Common Outcomes:
- The development of cancerous growths like basal cell carcinoma in less than 1% of nevus sebaceus cases
- The frequency of non-cancerous overgrowths may be higher
- Skin biopsy should be done on any suspicious skin growth within this type of blemish
- To prevent unnecessary invasive procedures, a skin disease expert should interpret the biopsy results
- Screenings for other cancers outside of the skin should be conducted based on symptoms and overall risk
Preventing Epidermal Nevus Syndromes
Patients and their family members should be informed about the low risk of some types of skin growths, known as epidermal nevi, turning into cancer. These skin growths may also be linked to other symptoms not related to the skin. If these situations apply, it’s recommended to seek further medical evaluations.