: We report a case of a 1-day-old neonate presenting with classic clinical and radiologic features of sacral agenesis, a rare congenital disorder. Early identification and multidisciplinary management are critical to improving outcomes. Case Presentation : A full-term, 1-day-old infant was examined for multiple congenital deformities. Physical f indings included a large head, round eyes, and a shallow chest. The lower limbs were short, internally rotated, and stiff, with minimal mobility at the hip and knee joints. External rotation of the hips was not possible, and both feet were turned inward.
A CT scan of the lumbar spine (without contrast) revealed normal cervical and thoracic vertebrae. However, one thoracic vertebra showed an unclear structure. At the spine’s end, a 2.0 × 1.5 × 1.1 cm spindle shaped mass with a density of +14 to +27 HU was seen under the skin on the right. The pelvis appeared underdeveloped, with an incomplete oblique fracture of the upper right midshaft femur. Upright radiography confirmed underdeveloped pelvic bones. The medial malleolus and tibia appeared symmetrical bilaterally. Epidemiology: Sacral agenesis (caudal regression syndrome) is a rare congenital condition with an estimated incidence of 1 in 100,000 live births. It is more common in infants born to mothers with pregestational diabetes, although it can occur sporadically. Both genetic and environmental factors may contribute.[11] Discussion : Sacral agenesis results from abnormal development of the caudal mesoderm during early embryogenesis, leading to partial or complete absence of the sacrum and sometimes lumbar spine. The severity ranges from isolated sacral agenesis to complete lumbosacral agenesis with associated genitourinary, gastrointestinal, and limb deformities. [8-10].
The current case presented with classic signs: bilateral lower limb deformities, limited joint mobility, underdeveloped pelvis, and a spinal abnormality. The presence of a spindle-shaped subcutaneous mass may represent a lipoma or associated spinal dysraphism. The incomplete femoral fracture may be due to birth trauma in the context of fragile bones or abnormal limb positioning.
Early imaging helps confirm the diagnosis and evaluate associated anomalies. Management typically involves orthopedic, neurologic, and urologic interventions. Long-term care focuses on mobility, continence, and developmental support. [13,14]. Conclusion: This case emphasizes the importance of recognizing sacral agenesis at birth through clinical examination and radiological imaging. Although rare, early diagnosis is vital for implementing supportive care and planning multidisciplinary interventions. Close follow-up is essential to monitor motor development and prevent complications. Ethical Considerations (EHT) : Ethical approval was obtained from the institutional review board. Parental consent was secured for the publication of clinical data and images. All procedures followed ethical standards of clinical care and the Helsinki Declaration. Confidentiality of patient information has been maintained throughout the report. No invasive procedures beyond standard diagnostics were performed. Acknowledgments The authors thank the Neonatology and Radiology Departments of Regional Diagnostic Center of Umnugovi Province for their contributions to the diagnosis and imaging. We also appreciate the cooperation of the child’s family and the medical ethics committee for guidance and approval. Special acknowledgment to the Division of Pediatric Neonatologists for their early intervention planning and support.