Figure 16-1. Pseudoxanthoma elasticum Multiple, confluent, chamois-colored or yellow papules (pseudoxanthomatous) create a large, circumferential, pebbled plaque on the neck of a 32-year-old woman. Changes in the connective tissue in this condition lead to excessive folds on the lateral neck.
Incidence. In mental institutions, 1:100 to 1:300; in general population, 1:20,000 to 1:100,000.
Age of Onset. Infancy.
Sex. Equal incidence.
Race. All races.
Heredity. Autosomal dominant. TS is caused by mutations in a tumor-suppressor gene, either TSCS1 or TSCS2. TSCS1 maps to chromosome 9q34. TSCS2 maps to 16p13.3.
Genetic alterations of ectodermal and mesodermal cells with hyperplasia, with a disturbance in embryonic cellular differentiation.
White macules are present at birth or appear in infancy (>80% occur by 1 year of age, 100% appear by 2 years); >20% of angiofibromata are present at 1 year of age, 50% occur by 3 years. Seizures (infantile spasms) occur in 86%; the earlier the onset of seizures, the worse the mental retardation. Mental retardation (49%).
Skin Lesions. 96% incidence.
Hypomelanotic Macules. “Off-white”; one or many, usually more than three. Polygonal or “thumbprint,” 0.5–2 cm; lance ovate or “ash-leaf” spots (Fig. 16-2), 3–4 cm (up to 12 cm); tiny white “confetti” macules, 1–2 mm (Fig. 16-3). White macules occur on trunk (>), lower extremities (>), upper extremities (7%), head and neck (5%). White macules shine up with Wood light (Fig. 16-2B)
Figure 16-2. Tuberous sclerosis: ash-leaflet hypopigmented macules (A) Three well-demarcated, elongated (ash-leaflet shaped), hypomelanotic macules on the lower leg of a child with tan skin. (B) Ash-leaflet hypomelanotic macules in pale skin are better visualized under Wood light where they light up.
Figure 16-3. Tuberous sclerosis: “confetti” macules Multiple, discrete, small, confetti-like, hypopigmented macules of variable size on the leg. These lesions are pathognomonic.
Angiofibromas. 0.1–0.5 cm, dome-shaped and smooth, exhibiting red or skin color (Fig. 16-4). Occur in the center of the face. They are firm and disseminated but may coalesce; termed adenoma sebaceum but represent angiofibromas (present in 70%).
Figure 16-4. Tuberous sclerosis: angiofibromas Confluent, small, angiomatous (erythematous, glistening) papules on the cheek and nose. These lesions were not present during the first few years of life; appeared only after the age of 4 years.
Plaques. Represent connective tissue nevi (“shagreen” patch), present in 40%; skin colored; occur on the back and buttocks (Fig. 16-5B).
Figure 16-5. Tuberous sclerosis: (A) Periungual fibroma (Koenen tumor). (B) Shagreen patch, slightly elevated, skin colored. This represents a connective tissue nevus.
Periungual Papules or Nodules. Ungual fibromas (Koenen tumors) present in 22%, arise late in childhood, and have the same pathology (angiofibroma) as the facial papules (Fig. 16-5A).
CNS (tumors producing seizures), eye (gray or yellow retinal plaques, 50%), heart (benign rhabdomyomas), hamartomas of mixed cell type (kidney, liver, thyroid, testes, and GI system).
Dermatopathology. White Macules. Decreased number of melanocytes, decreased melano-some size, decreased melanin in melanocytes and keratinocytes.
Angiofibromata. Proliferation of fibroblasts, increased collagen, angioneogenesis, capillary dilatation, absence of elastic tissue.
Brain Pathology. “Tubers” are gliomas.
Imaging. Skull X-Ray. Multiple calcific densities.
CT Scan. Ventricular deformity and tumor deposits along the striothalamic borders.
MRI. Subependymal nodules.
Renal Ultrasound. Reveals renal hamartoma.
More than five ash leaf macules (Fig. 16-2) in an infant are highly suggestive. Confetti spots (Fig. 16-2) are virtually pathognomonic. Evaluate the patient with a study of the family members and by obtaining various types of imaging as well as electroencephalography. Mental retardation and seizures may be absent.
White Spots. Focal vitiligo, nevus anemicus, tinea versicolor, nevus depigmentosus, postinflammatory hypomelanosis.
Angiofibromas. Tricholemmoma, syringoma, skin-colored papules on the face, dermal nevi.
Note: angiofibromata of the face (Fig. 16-4) have been mistaken for and treated as acne vulgaris or rosacea.
Periungual Fibromas. Verruca vulgaris.
Course and Prognosis
A serious autosomal disorder that causes major problems in behavior, because of mental retardation, and in therapy, to control the serious seizure problem present in many patients.
Treatment. Laser surgery for angiofibromas.
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