Dysplastic spondylolisthesis is a developmental subtype characterized by congenital lumbosacral abnormalities and progressive instability. Primary presentation with cauda equina syndrome (CES) has rarely been reported. We report a rare case of CES associated with highgrade dysplastic spondylolisthesis in a patient with concurrent giant ovarian teratomas, which contributed to delayed diagnosis and treatment because of overlapping pelvic symptoms. The patient presented with progressive urinary dysfunction, saddle anesthesia, and lower- extremity symptoms. Radiographic evaluation demonstrated high-grade L5–S1 dysplastic spondylolisthesis with severe canal compromise and lumbosacral deformity. Surgical treatment involved neural decompression and controlled deformity correction with sacral dome osteotomy and interbody fusion performed under provisional stabilization. Postoperatively, the patient demonstrated meaningful neurological recovery with improvement of urinary symptoms and restoration of lumbosacral alignment. This case highlights that CES can occur as an initial manifestation of dysplastic spondylolisthesis and underscores the importance of early spinal evaluation and timely surgical treatment with appropriate reduction techniques to prevent further neurological deterioration in patients with persistent neurological symptoms.