In the scalp, these defects usually occur over the posterior fontanelle astride the midline. Observed at birth, they are sharply demarcated and appear to be covered by a transparent membrane. After birth, the very thin membrane is easily disrupted, resulting in hemorrhage that requires hemostatic dressings. If the lesion is very small and superficial, the resulting ulceration will heal with cicatrix or keloid formation. Although the defect most frequently involves only the epidermis and dermis, there may be an associated periosteal and osseous defect underlying the lesion.
Defects involving the extremities are usually symmetrical and involve only the skin as a rule.
Occasionally, however, they involve the deeper structures and even the underlying muscle. The mainstay of treatment is control of infection and hemorrhage. Small defects may be left to epithelialize or be covered with split-skin graft. Large defects need a local flap and later treatment of scars and alopecia. References Campbell W. Case of congenital ulcer on the cranium of a fetus, terminating in fatal hemorrhage on the 18th day after birth.