A rare symptomatic L5–S1 anterior retroperitoneal lumbar disc herniation causing foot drop and mimicking a peripheral nerve sheath tumor: illustrative case

This case highlights the difficulty in differentiating enhancing presacral retroperitoneal lesions using neuroimaging alone, and that tissue biopsy and histopathological evaluation remain essential for accurate diagnosis. The anterior retroperitoneal corridor proved a safe and effective approach for obtaining tissue for accurate diagnosis and guiding the optimal ongoing management. https://thejns.org/doi/10.3171/CASE25977.