Skin Dimples

Cutaneous depressions over bony prominences and in the acral area, at times associated with pits and creases, may occur in normal children and in association with dysmorphologic syndromes. Skin dimples may develop in utero as a result of interposition of tissue between a sharp bony point and the uterine wall, which leads to decreased subcutaneous tissue formation.

Dimples may also be present overlying an area of bone hypoplasia. Bilateral acromial skin dimples are usually an isolated finding, but they are also seen in association with deletion of the long arm of chromosome 18. Dimples tend to occur over the patella in congenital rubella, over the lateral aspects of the knees and elbows in prune-belly syndrome, on the pretibial surface in campomelic dwarfs, and in the shape of an H on the chin in whistling-face syndrome.

Sacral dimples are common and usually are isolated findings. They may be seen in multiple syndromes or in association with spina bifida occulta and diastomyelia. Association with a mass or other cutaneous stigma (hair, aplasia cutis, hemangioma) should increase concern for underlying spinal dysraphism (Chapter 585). Ultrasonography during the first 3 mo of life, before ossification of the posterior elements of the lower spine, may provide a cost-effective, noninvasive method of assessing any associated lumbosacral spine abnormalities.

Redundant Skin

Loose folds of skin must be differentiated from a congenital defect of elastic tissue or collagen such as cutis laxa, Ehlers-Danlos syndrome, or pseudoxanthoma elasticum. Redundant skin over the posterior part of the neck is common in the Turner, Noonan, Down, and Klippel-Feil syndromes and monosomy 1p36; more generalized folds of skin occur in infants with trisomy 18 and short-limbed dwarfism.

Amniotic Constriction Bands

Partial or complete constriction bands that produce defects in extremities and digits are found in 1/10,000-1/45,000 otherwise normal infants. Constrictive tissue bands are caused by primary amniotic rupture, with subsequent entanglement of fetal parts, particularly limbs, in shriveled fibrotic amniotic strands. This event is probably sporadic, with negligible risk of recurrence. Formation of constrictive tissue bands is associated with abdominal trauma, amniocentesis, and hereditary defects of collagen such as Ehlers-Danlos syndrome and osteogenesis imperfecta.

Adhesive bands involve the craniofacial area and are associated with severe defects such as encephalocele and facial clefts. Adhesive bands result from broad fusion between disrupted fetal parts and an intact amniotic membrane. The craniofacial defects appear not to be caused by constrictive amniotic bands but to result from a vascular disruption sequence with or without cephaloamniotic adhesion (Chapter 102).

The limb–body wall complex (LBWC) involves vascular disruption early in development, affecting several embryonic structures; it includes at least 2 of the following 3 characteristics: exencephaly or encephalocele with facial clefts, thoracoschisis and/or abdominoschisis, and limb defects.

Preauricular Sinuses and Pits

Pits and sinus tracts anterior to the pinna may be a result of imperfect fusion of the tubercles of the 1st and 2nd branchial arches. These anomalies may be unilateral or bilateral, may be familial, are more common among females and blacks, and at times are associated with other anomalies of the ears and face. Preauricular pits are present in branchio-otorenal dysplasia 1 syndrome (EYA-1 gene), an autosomal dominant disorder that consists of external ear malformations, branchial fistulas, hearing loss, and renal anomalies. When the tracts become chronically infected, retention cysts may form and drain intermittently; such lesions may require excision.

Accessory Tragi

An accessory tragus typically appears as a single pedunculated, flesh-colored papule in the preauricular region anterior to the tragus. Less commonly, accessory tragi are multiple or bilateral, and may be located in the preauricular area, on the cheek along the line of the mandible (Fig. 640-1), or on the lateral aspect of the neck anterior to the sternocleidomastoid muscle. In contrast to the rest of the pinna, which develops from the 2nd branchial arch, the tragus and accessory tragi derive from the 1st branchial arch. Accessory tragi may occur as isolated defects or in chromosomal 1st branchial arch syndromes that include anomalies of the ears and face, such as cleft lip, cleft palate, and mandibular hypoplasia. An accessory tragus is consistently found in oculo-auriculo-vertebral syndrome (Goldenhar syndrome). Surgical excision is appropriate.

Figure 640-1 Accessory tragus on cheek along jaw line.

Branchial Cleft and Thyroglossal Cysts and Sinuses

Cysts and sinuses in the neck may be formed along the course of the 1st, 2nd, 3rd, or 4th branchial clefts as a result of improper closure during embryonic life. Second branchial cleft cysts are the most common. The lesions may be unilateral or bilateral (2-3%) and may open onto the cutaneous surface or drain into the pharynx. Secondary infection is an indication for systemic antibiotic therapy. These anomalies may be inherited as autosomal dominant traits.

Thyroglossal cysts and fistulas are similar defects located in or near the midline of the neck; they may extend to the base of the tongue. A pathognomonic sign is vertical motion of the mass with swallowing and tongue protrusion. In nearly 50% of affected children, the cyst or fistula manifests as an infected midline upper neck mass. Cysts in the tongue base may be differentiated from an undescended lingual thyroid by radionuclide scanning. Unlike branchial cysts, a thyroglossal duct cyst often appears after an upper respiratory infection (Chapter 557).

Supernumerary Nipples

Solitary or multiple accessory nipples may occur in a unilateral or bilateral distribution along a line from the anterior axillary fold to the inguinal area. They are more common among black (3.5%) than white (0.6%) children. Accessory nipples may or may not have areolae and may be mistaken for congenital nevi. They may be excised for cosmetic reasons. Renal or urinary tract anomalies and hematologic abnormalities may occur in children with this finding (Chapter 545).

Aplasia Cutis Congenita (Congenital Absence of Skin)

Developmental absence of skin is usually noted on the scalp as multiple or solitary (70%), noninflammatory, well-demarcated, oval or circular 1- to 2-cm ulcers. The appearance of lesions varies, depending on when they occurred during intrauterine development. Those that form early in gestation may heal before delivery and appear as atrophic, fibrotic scars with associated alopecia, whereas more recent defects may manifest as ulcerations. Most occur at the vertex just lateral to the midline, but similar defects may also occur on the face, trunk, and limbs, where they are often symmetric. The depth of the ulcer varies. Only the epidermis and upper dermis may be involved, resulting in minimal scarring or hair loss, or the defect may extend to the deep dermis, to the subcutaneous tissue, and, rarely, to the periosteum, skull, and dura. Lesions may be surrounded by a collar of hair (Fig. 640-2).

Figure 640-2 Solitary scalp vertex lesion of aplasia cutis congenita with hair collar.

Diagnosis is made on the basis of physical findings indicative of in utero disruption of skin development. Lesions are sometimes mistakenly attributed to scalp electrodes or obstetric trauma.

Although most individuals with aplasia cutis congenita have no other abnormalities, these lesions may be associated with isolated physical anomalies or with malformation syndromes, including Opitz, Adams-Oliver, oculocerebrocutaneous, Johanson-Blizzard, and 4p(-), X-p22 microdeletion syndromes, trisomy 13-15, and chromosome 16-18 defects. Aplasia cutis congenita may also be found in association with an overt or underlying embryologic malformation, such as meningomyelocele, gastroschisis, omphalocele, or spinal dysraphism. Aplasia cutis congenita in association with fetus papyraceus is apparently due to ischemic or thrombotic events in the placenta and fetus. Blistering or skin fragility and/or absence or deformity of nails in association with aplasia cutis congenita is a well-recognized manifestation of epidermolysis bullosa. Aplasia cutis may be confused with traumatic skin injury from monitoring devices and spontaneous atrophic patches (anetoderma) of prematurity.

Major complications are hemorrhage, secondary local infection, and meningitis. If the defect is small, recovery is uneventful, with gradual epithelialization and formation of a hairless atrophic scar over a period of several weeks. Small bony defects usually close spontaneously in the 1st year of life. Large or numerous scalp defects may require excision. Truncal and limb defects, despite being large, usually epithelialize and form atrophic scars, which can later be revised.

Focal Facial Ectodermal Dysplasia (Bitemporal Aplasia Cutis Congenita, Ectodermal Dysplasia of the Face)

The rare disorder known as focal facial ectodermal dysplasia is characterized by congenital atrophic scar–like lesions on the temples. Sweating is absent over the defects, the lateral third of the eyebrows is sparse, and linear vertical wrinkles are present on the forehead. Autosomal dominant and autosomal recessive inheritances have been documented; patients with both types lack associated facial anomalies. Patients with Setleis syndrome have bitemporal scarring in association with leonine facies, nasal bridge abnormalities, low frontal hairline, and normal growth and development.

Focal Dermal Hypoplasia (Goltz Syndrome)

A rare congenital mesoectodermal and ectodermal disorder, focal dermal hypoplasia is characterized by dysplasia of connective tissue in the skin and skeleton. This disorder is an X-linked dominant disorder caused by mutations in the PORCN gene. It manifests as numerous soft tan papillomas. Other cutaneous findings include linear atrophic lesions; reticulated hypopigmentation and hyperpigmentation; telangiectasias; congenital absence of skin; angiofibromas presenting as verrucous excrescences; and papillomas of the lips, tongue, circumoral region, vulva, anus, and the inguinal, axillary, and periumbilical areas. Partial alopecia, sweating disorders, and dystrophic nails are additional, less common ectodermal anomalies. The most frequent skeletal defects are syndactyly, clinodactyly, polydactyly, and scoliosis. Osteopathia striata are fine parallel vertical stripes noted on radiographs in the metaphyses of long bones of patients with this disorder; these are highly characteristic of focal dermal hypoplasia but are not pathognomonic. Many ocular abnormalities, the most common of which are colobomas, strabismus, nystagmus, and microphthalmia, are also characteristic. Small stature, dental defects, soft tissue anomalies, and peculiar dermatoglyphic patterns are also common. Mental deficiency occurs occasionally.

Dyskeratosis Congenita (Zinsser-Engman-Cole Syndrome)

Dyskeratosis congenita, a rare familial syndrome, consists classically of the triad of reticulated hyperpigmentation of the skin (Fig. 640-3), dystrophic nails, and mucous membrane leukoplakia in association with immunologic and hematologic abnormalities. Patients with dyskeratosis congenita also show signs of premature aging and increased occurrence of cancer, especially squamous cell carcinoma. Dyskeratosis congenita may be X-linked recessive (DKC-1 gene), autosomal dominant (hTERC and TINF2 genes), or autosomal recessive (NOLA3 gene). Onset occurs in childhood, most commonly as nail dystrophy. The nails become atrophic and ridged longitudinally with progression to pterygia and complete nail loss. Skin changes usually appear after onset of nail changes and consist of reticulated gray-brown pigmentation, atrophy, and telangiectasia, especially on the neck, face, and chest. Hyperhidrosis and hyperkeratosis of the palms and soles, sparse scalp hair, and easy blistering of the hands and feet are also characteristic. Blepharitis, ectropion, and excessive tearing due to atresia of the lacrimal ducts are occasional manifestations. Oral leukokeratosis may give rise to squamous cell carcinoma. Other mucous membranes, including conjunctival, urethral, and genital, may be involved. Infection, malignancy, and bone marrow failure are common, and death before age 40 yr is typical (Chapter 462).

Figure 640-3 Reticulated dyspigmentation on neck of patient with dyskeratosis congenita.

Cutis Verticis Gyrata

Cutis verticis gyrata, an unusual alteration of the scalp that is more common in males, may be present from birth or may develop during adolescence. The scalp is characterized by convoluted elevated folds, 1-2 cm in thickness, usually in the fronto-occipital axis. Unlike the lax skin of other disorders, the convolutions cannot generally be flattened by traction. Primary cutis gyrata may be associated with mental retardation, retinitis pigmentosa, sensorineural deafness, and thyroid aplasia. Secondary cutis gyrata may be due to chronic inflammatory diseases, tumors, nevi, and acromegaly.