A 1-day-old full-term 3140 gram male neonate presented with large symmetric skin defects of the scalp, trunk, and extremities. Intrauterine fetal demise of a twin was reported between 16-18 weeks of gestation. The parents were non-consanguineous. No other family members were similarly affected. Aplasia cutis congenita (ACC) reflects a spectrum of cutaneous and subcutaneous tissue defects. Most frequently, aplasia cutis congenita presents as a small, isolated defect in the scalp of neonates along the lines of embryonic fusion. This limited form of aplasia cutis congenita must be distinguished from traumatic ulceration from scalp electrode placement in the perinatal time period and congenital or neonatal herpes simplex infection.
Frieden has classified ACC into nine subtypes, based on clinical presentation, prognosis, and associated conditions. Type V ACC is associated with a fetus papyraceus, or mummified co-twin present at birth. The fetus papyraceus is formed after the co-twin dies early in the second trimester. This rarely described entity presents as isolated extensive symmetric areas of cutaneous and subcutaneous skin defects. Areas of skin aplasia generally heal well, albeit with scarring, and infection – with the exception of extensive scalp ACC – is not usually a problem.
The etiology of ACC remains poorly elucidated. Clearly, genetic predisposition plays a role in the development of this disorder, but other factors, including intrauterine infection, amniotic adhesions, intrauterine necrosis, and teratogens may play a role. Additionally, some authors have proposed that areas of aplasia result from watershed areas of necrosis due to impaired vascular supply. Similarly, scalp aplasia has been proposed as a result of tissue tension in the setting of head growth leading to a further impaired vascular supply and tissue necrosis. Type V ACC associated with fetus papyraceus may result from vascular compromise secondary to the co-twin’s demise in the early 2nd trimester. In our patient the scars in the groin and axillae represent areas of aplasia that healed over the ensuing months of gestation between the insult and birth.
ACC may be associated with a number of complications. One case of ACC reported by Campbell was complicated by fatal sagittal sinus hemorrhage 18 days postpartum. Estimates suggest that the mortality rate of patients with extensive scalp ACC may be as high as 20-30 percent . Death is generally a result of hemorrhage, thrombosis, or infection. Prompt diagnosis and appropriate management are critical in avoiding adverse outcomes. This patient underwent successful plastic surgical repair and continues to do well postoperatively.
References:
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