Bilateral Patellar Aplasia Cutis Congenita: Clinical Management and Reconstructive Considerations—a Case Report

Background: Aplasia cutis congenita (ACC) is a rare congenital disorder characterized by localized absence of the skin, most commonly affecting the scalp. Bilateral involvement of the patellar region is exceptionally uncommon. We report an isolated case of bilateral patellar ACC in the surviving twin following a monochorionic diamniotic twin pregnancy complicated by selective fetoscopic laser photocoagulation and discuss the successful outcome of conservative management. Case Presentation: A female neonate was delivered by cesarean section at 38 weeks and 4 days of gestation after a monochorionic diamniotic twin pregnancy in which selective fetoscopic laser photocoagulation with termination of the affected co-twin had been performed at 13 weeks and 4 days of gestation because of multiple severe congenital anomalies. At birth, asymmetric bilateral patellar skin defects were identified. The left knee demonstrated an approximately 3 × 4 cm full-thickness cutaneous defect with exposed patellar periosteum, whereas the right knee exhibited a superficial epidermal defect. No associated congenital anomalies were identified, and the diagnosis of ACC was established clinically following multidisciplinary evaluation. Given the clean, well-vascularized wound bed, absence of exposed joint structures or infection, and preserved tissue viability, conservative treatment consisting of daily non-compressive dressings, topical bacitracin–neomycin, and prophylactic intravenous ampicillin–sulbactam was initiated. Progressive epithelialization was achieved without complications, and complete wound healing with preserved knee function was observed without surgical intervention. Conclusions: This case demonstrates that selected periarticular ACC lesions, even in the presence of exposed patellar periosteum, can be successfully managed with conservative treatment when careful multidisciplinary assessment confirms favorable wound characteristics. In addition, this report expands the limited literature on bilateral patellar ACC occurring in the setting of a complicated monochorionic diamniotic twin pregnancy.