A Rare Case of Aplasia Cutis Congenita of the Scalp with Dual Skin Defects in a Non-Syndromic Preterm Newborn

Aplasia Cutis Congenita (ACC) is a rare congenital condition characterized by localized or widespread absence of skin at birth. It most commonly affects the scalp and can be classified into different subtypes based on clinical presentation and associated anomalies. The exact etiology remains unclear, with genetic predisposition, vascular compromise, teratogen exposure, and maternal factors being implicated. This case is of a preterm male neonate, born at 35 weeks of gestation to a 40-year-old primigravida mother with a history of hypothyroidism and long-term thyroxine use. The mother conceived via in vitro fertilization (IVF) after undergoing extensive fertility treatments. At birth, the neonate exhibited two well-demarcated skin defects over the left posterior parietal triangle of the scalp, without involvement of deeper structures. Clinical diagnosis of non-syndromic membranous scalp ACC was made. Conservative management with saline cleansing and topical antibiotic application was adopted. The lesions healed completely by six months with residual atrophic scarring and a ‘hair collar sign’. This case highlights a rare instance of isolated ACC in a neonate with a unique maternal history of hypothyroidism, prolonged thyroxine use, and IVF-conceived pregnancy. The successful conservative management further supports its role in appropriately selected cases.