Tuberous Sclerosis Complex (TSC) causes benign tumors to grow in a number of different regions of the body, including the skin. Experts estimate that more than 90 percent of individuals with TSC exhibit one or more of five types of these skin abnormalities, which are benign and generally harmless. However, in some cases, they may cause physical discomfort and may be psychologically distressing to people who have them.
The high frequency of skin abnormalities in people with TSC—and the relative ease of observing them—make these symptoms important in diagnosing the disorder. Physicians often base a TSC diagnosis, at least in part, on the presence of a combination of skin lesions and other abnormalities common or unique to the disorder. The five main types of skin abnormalities (in order of frequency) include:
Hypomelanotic macules, or hypopigmented macules, are not lesions, but simply patches of skin lighter than the surrounding area. They vary in size from several millimeters to several centimeters in diameter. They also vary in shape but are generally elliptical or lance shaped (commonly called "ash leaf" shaped). These harmless "white spots," as they are sometimes called, are seen in more than 90 percent of people with TSC, and unlike many other skin lesions associated with the disorder, they are common in infants with TSC. The presence of three or more hypomelanotic macules is considered a major feature in the TSC diagnostic criteria and serves as an important sign of the disorder. In some cases, especially in people with particularly light skin, physicians may use a type of ultraviolet light known as a Wood's lamp to see hypomelanotic macules that may not be visible otherwise.
Facial AngiofibromasFacial angiofibromas are small reddish spots or bumps that consist of fibrous tissue and blood vessels. They are most commonly found around the nose, cheeks, and chin, often combining to form a distinctive butterfly-shaped pattern. Angiofibromas typically appear in people with TSC between age two and age five, but may arise earlier or later in life. Early on, angiofibromas tend to be relatively bright red and level with the skin surface, but over time become thicker, more fibrous, and more numerous. Although angiofibromas are unique to TSC and considered a major feature in the TSC diagnostic criteria, they are sometimes mistaken for other skin disorders, including acne. Also, because angiofibromas seldom appear in children younger than two years of age, they are of little use in diagnosing TSC in infants and very young children.
Shagreen patches are firm yellowish-red or pink nodules slightly elevated above the surrounding skin. The surface of a shagreen patch is often described as having the texture of an orange peel. Shagreen patches vary in size from a few millimeters to more than 10 cm in diameter. If present, they are nearly always found on or around the lumbar region of the back. They typically first appear before or around puberty, but are sometimes seen in children as young as six months old. The patches may increase in number over time and typically grow in proportion to body size until adulthood. Because shagreen patches are characteristic of TSC, they are considered a major feature in the TSC diagnostic criteria.
Similar to shagreen patches, forehead plaques are fibrous, flesh-colored patches raised above the surface of the surrounding skin. They arise on the forehead or scalp and vary in size from a few millimeters to several centimeters in diameter. They may be smooth or rough in texture. In some children, forehead plaques may be obvious at birth or may appear shortly after birth. In some cases, they represent the first external symptoms of TSC. Experts classify forehead plaques as angiofibromas, and like facial angiofibromas, they are considered a major feature in the TSC diagnostic criteria. Although these lesions resemble shagreen patches, they are more closely related to facial angiofibromas. As a result, the two are grouped together for the purpose of clinical diagnosis.
Periungual fibromas are flesh-colored or reddish lesions that grow around and under fingernails and toenails. These tumors generally arise from the nail bed or from the skin around the perimeter of the nail. Periungual fibromas vary in size from a few millimeters to about 1 cm in diameter. They are more common on the toes than on the fingers, where their growth may be stimulated by the rubbing of shoes. Periungual fibromas are characteristic of TSC and are considered a major feature in the diagnostic criteria, with multiple lesions being a more reliable diagnostic sign than a single lesion. However, because periungual lesions typically do not appear until puberty, their usefulness in diagnosing very young children is limited.
There are other skin lesions associated with TSC, but because none are specific to the disorder, or because they are relatively uncommon, their usefulness in diagnosing TSC is limited. These include:
- Confetti-like lesions—small, lightly pigmented spots 1-2 mm in diameter
- Skin tags—multiple small soft growths that protrude from the skin, especially in the neck and groin regions
- Café-au-lait spots—flat, darkly pigmented spots that are more commonly associated with the genetic disorder neurofibromatosis 1, or NF1, but may be more prevalent in people with TSC than in the general public
Follow-up and Treatment
As with other manifestations of TSC, skin lesions caused by the disorder are highly variable from one individual to another, and from one life stage to the next. Some people with TSC may have only hypomelanotic macules or small numbers of facial angiofibromas, while others may see more severe abnormalities in their skin. Although skin lesions seldom lead to serious physiological complications, they can cause physical discomfort and psychological distress. For this reason, adequate monitoring and intervention are important.
Fortunately, recent advances in laser surgery and other treatment options have made living with some of TSC's manifestations in the skin far more bearable.
The most commonly treated TSC-related skin lesions are facial angiofibromas. Treatment becomes important especially for adolescents and young adults when the lesions become more pronounced and more psychologically distressing as a result. In young men, blood-rich angiofibromas can also bleed significantly when they are nicked during shaving.
Although dermatologists have used many techniques to remove angiofibromas, including dermabrasion, shave excision, cryosurgery, and others, the most promising treatment uses various types of lasers to eradicate the fibrous tissue and blood vessels that make up the tumors. The technique usually requires only a local anesthetic, depending on the age of the patient, and most people recover fully within a week to 10 days. Although some research suggests that early intervention may prevent angiofibromas from growing, many experts remain unconvinced that laser treatment can be preventative.
Unfortunately, laser treatments are relatively expensive and, as with other techniques, must be repeated periodically. TSC skin lesions are dynamic, which means that when they are removed or destroyed, they grow back, so treatments must be recurring to be successful.
Dermatologists remove periungual fibromas using both lasers and surgical excision. This becomes necessary when the lesions become physically uncomfortable, especially those that are prone to bleeding, or those that are large and cause difficulties with wearing shoes.
Shagreen patches and forehead plaques can also be treated using lasers. However, because the lesions can grow back, and because laser treatments cause scarring, most dermatologists recommend this option only for very large and particularly disfiguring patches and plaques.
Individuals with TSC should see a dermatologist or cosmetic surgeon who has experience treating people with TSC. If treatment is indicated, these doctors should be qualified surgeons who have experience dealing with medical skin conditions.
Some cosmetic companies also manufacture makeup to cover hypomelanotic macules if they are large or in exposed areas of the skin. For some individuals, the hypomelanotic macules are not problematic, whereas others will choose to cover them with clothing or makeup.
It is important to remember:
- The five most common types of skin abnormalities that affect people with TSC are: hypomelanotic macules, facial angiofibromas, shagreen patches, forehead plaques and periungual fibromas
- Accurate identification of these skin abnormalities is often instrumental in the diagnosis of TSC
- TSC-related skin tumors are benign and generally harmless
- Most TSC skin abnormalities become more pronounced with age
- Although the health effects of most TSC skin abnormalities are mild, they can cause physical discomfort and psychological distress
- Careful monitoring by a dermatologist or physician experienced with TSC can result in more successful treatment of skin lesions should intervention become necessary
- Make sure your dermatologist is familiar with TSC-related skin abnormalities
- Make sure your cosmetic surgeon has experience dealing with medical skin conditions
Tuberous Sclerosis Complex Glossary
Explanations of common terms you'll encounter when learning about TSC.
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