Background: Fetoscopic laser photocoagulation can directly injure fetal skin and may at birth resemble aplasia cutis congenita (ACC). Case report: A twin monochorionic pregnancy was complicated by twin-to-twin transfusion syndrome requiring in utero laser photocoagulation, resulting in the death of one twin. After birth, the viable baby presented skin lesions in both legs that were congruent with laser-induced burns. Conclusions: Laser-induced burns present as asymmetric superficial non-necrotic or ulcerated lesions, with a geographic outline, which turn into scars with no retraction or contractures and no changes in pain perception or motor limitations over time. ACC lesions are bilateral and symmetric, with a regular outline, an ulcerated or necrotic appearance, a higher degree of skin involvement affecting all skin layers and, over time, they turn into scars with retraction and contractures. These differential features may help clinicians in a challenging approach to the diagnosis of congenital skin defects.
Keywords: congenital skin defects; laser photocoagulation; twin-to-twin transfusion syndrome; vanishing twin.