The hallmark of aplasia cutis congenita in the neonatal period is the presence of a solitary well-demarcated skin punch-out lesion (Figure 305.1). Multiple lesions may also occur. Aplasia cutis congenita must be differentiated from traumatic cutaneous lesions (fetal monitor injuries). Aplasia cutis congenita may be isolated or it may occur with Trisomy 13, 4p-syndrome, ectodermal dysplasia, and amniotic bands. Aplasia cutis in the hair whirl area is usually a benign finding. Neonates with aplasia cutis congenita in the craniofacial and lumbosacral regions should undergo MRI or ultrasound to evaluate the central nervous system structures below it. Isolated aplasia cutis congenita is usually sporadic.

Figure 305.1.— Typical punch-out lesion of aplasia cutis congenita in the lumbar region.