Lumbosacral Midline Aplasia Cutis Congenita Without Spinal Dysraphism on Magnetic Resonance Imaging: A Case Report

Introduction: Aplasia cutis congenita is a focal absence of skin at birth and involves the scalp in the vast majority of cases. When located on the lumbosacral midline, it is regarded as a high-risk cutaneous marker of occult spinal dysraphism, which warrants investigation of the neuraxis. Case report: A male late preterm newborn (35 weeks and 1 day), large for gestational age, was born to a mother with type 1 diabetes mellitus, chronic hypertension, obesity and preeclampsia. On neonatal examination, he had an erosive lesion with a membranous appearance on the lumbosacral midline, without discharge, and preserved posture, tone, strength and primitive reflexes. The neonatal team raised the hypothesis of closed lumbosacral dysraphism, and the lesion was managed with a silicone foam dressing following neurosurgical advice. Lumbosacral radiography at 23 days of life showed no abnormalities. Contrast-enhanced magnetic resonance imaging performed under sedation at 8 months showed a conus medullaris of normal morphology, position and signal, a spinal canal of preserved caliber and no pathological enhancement. Neonatal screening and cardiac, ophthalmological and hearing assessments revealed no relevant associated anomalies, and growth remained adequate. Discussion: Lumbosacral aplasia cutis should be managed as a high-risk marker, especially when maternal factors increase the likelihood of neural tube defects, but it may occur without an underlying spinal malformation. Conclusion: Clinical and radiological correlation made it possible to rule out structural dysraphism, although follow-up of neurological, urological and orthopedic development remains necessary.