Upper lumbar spine far lateral disc herniations masquerading as peripheral nerve sheath tumors: illustrative cases

Abstract

BACKGROUND Migratory disc herniations can mimic neoplasms clinically and on imaging. Far lateral lumbar disc herniations usually compress the exiting nerve root and can be challenging to distinguish from a nerve sheath tumor due to the proximity of the nerve and characteristics on magnetic resonance imaging (MRI). These lesions can occasionally present in the upper lumbar spine region at the L1–2 and L2–3 levels. OBSERVATIONS The authors describe 2 extraforaminal lesions in the far lateral space at the L1–2 and L2–3 levels, respectively. On MRI, both lesions tracked along the corresponding exiting nerve roots with avid postcontrast rim enhancement and edema in the adjacent muscle tissue. Thus, they were initially concerning for peripheral nerve sheath tumors. One patient underwent fluorodeoxyglucose positron emission tomography–computed tomography (FDG PET-CT) screening and demonstrated moderate FDG uptake on PET-CT scan. In both cases, intraoperative and postoperative pathology revealed fibrocartilage disc fragments. LESSONS Differential diagnosis for lumbar far lateral lesions that are peripherally enhancing on MRI should include migratory disc herniation, regardless of the level of the disc herniations. Accurate preoperative diagnosis can aid in decision making for management, surgical approach, and resection.

Thoracic root–related intradural extramedullary cavernoma presenting with subarachnoid hemorrhage: illustrative case

“…Numerous cases of MRI-related misdiagnoses or imprecise definitions have been published. 1 , 23 , 24 Even with gadolinium-enhanced sequences, it can be challenging to distinguish between a degenerative condition such as a disc herniation and a neoplastic entity. This difficulty arises because of varying patterns of enhancement influenced by local inflammatory responses, potentially leading to an inaccurate diagnosis.…”

“…Cases of sequestrated discs masquerading as tumors and vice versa have been described. 23 , 25 Different MRI approaches and sequences have been developed and proposed to overcome these diagnostic hindrances.…”