Surgical management of symptomatic retroperitoneal migratory disc herniation anterior to the sacral ala causing L5 radiculopathy using direct decompression and fusion: illustrative case.

Background Atypical lumbar disc herniations, such as migratory extreme lateral and intradural herniations, can mimic malignancy on imaging, complicating diagnosis and treatment. These herniations can involve unusual locations, such as the retroperitoneal or presacral area. Migratory herniations, in particular, can appear similar to peripheral nerve sheath tumors, presenting diagnostic challenges.Observations The authors present the case of a 39-year-old male with symptomatic migratory extreme lateral disc herniation causing L5 radiculopathy. Initial MRI suggested a peripheral nerve sheath tumor, and positron emission tomography/CT (PET/CT) showed minimal metabolic activity. Biopsy confirmed a migratory disc herniation, which was treated with anterior lumbar interbody fusion at L5-S1 via a pararectus approach. The patient showed significant pain relief and improvement in hypoesthesia postsurgery, but L5 motor weakness remained unchanged.Lessons Imaging can be unreliable in distinguishing migratory disc herniation from tumors. Although MRI and PET/CT are standard tools, they can show features that overlap with neoplastic processes. Histopathological evaluation remains crucial for accurate diagnosis. The pararectus approach provides excellent access for biopsy and direct decompression in cases of atypical herniations, minimizing recurrence risk while addressing concurrent disc degeneration. This case highlights the importance of comprehensive imaging and interdisciplinary discussions when diagnosing and treating rare disc herniations, with the pararectus approach offering a viable surgical solution for these challenging cases. Surgeons should consider atypical herniation locations when diagnosing lumbar radiculopathy, especially in cases where imaging is inconclusive. For retroperitoneal herniations, the pararectus approach allows for both diagnostic biopsy and effective surgical management, including decompression and fusion in a single procedure. https://thejns.org/doi/10.3171/CASE24866.