Noninflammatory and well-demarcated lesions have
different shapes, with diameters ranging from 0.5 to 10 cm and dilated scalp
veins radiating from the periphery of scalp defect. The defect often is
located in the area of the vertex of the skull. In a few cases, almost
complete absence of skin and skull bone (partial acrania) has been reported
and associated with high mortality (infection, hemorrhage). The aspect
of the lesions is quite variable because it depends upon the stage of
uterine development when the insult occurs. Defects caused early in
gestation may be healed before birth and appear as an atrophic transparent
membrane or a fibrotic scar. However, defects that develop later in
gestation may present as ulcerations of variable depth. Although most
defects are limited to the epidermis, occasionally the ulcerations are deep
and involve the underlying subcutaneous, periosteal, and osseous tissues or
even the meninges. On the scalp, the alopecic and scarred area usually is
surrounded by a rim of abnormal hair growth, known as the hair collar sign. Small defects
usually heal under formation of an atrophic scar, and underlying osseous
lesions close spontaneously within the first year of life. However,
extensive or multiple lesions may require surgical excision and plastic
surgery (skin grafting, tissue expanders, flaps) to close the defects. Aside
from the formation of atrophic scars, truncal and limb defects heal
surprisingly well. Other findings may include chest with pectus excavatum,
supernumerary nipples, and Poland Syndrome. Congenital cardiac lesions,
such as tetralogy of Fallot, pulmonary valvular atresia, and ventricular
septal defects, have been described in some patients. Various neurologic
anomalies include mental retardation, seizures, spasticity, hemiparesis,
encephalocele or exencephaly, porencephaly, and schizencephaly. Other
features may affect the eyes (strabismus, microphthalmia) and genitourinary
tract (cryptorchidism, renal duplication). Cutis marmorata telangiectatica
congenita and dermatoglyphic abnormalities may be associated with ACC.