Diffuse cauda equina nerve root enlargement: diagnostic challenges, clinicopathological spectrum, and the role of
Chunli Lu1,2,3, Xingwen Wang2, Min Yin4
1Department of Spine Surgery, Qilu Hospital of Shandong University (Qingdao), Cheeloo College of Medicine, Shandong University, Qingdao, Shandong, China.
Backgrounds:
Diffuse enlargement of the cauda equina nerve roots is an uncommon radiological finding that may result from various causes, including neoplastic, inflammatory, and immune-mediated conditions. Because these causes have overlapping imaging features, it remains challenging to differentiate among them, and effective diagnostic strategies are not well established.
Purpose:
To characterize the clinicoradiological features of patients presenting with diffuse cauda equina root enlargement and to evaluate the diagnostic role of surgical biopsy in cases with uncertain etiology.
Methods:
We retrospectively reviewed 12 patients presenting with symptoms of cauda equina and nerve root involvement, along with diffuse nerve root enlargement on MRI, between 2019 and 2024. Clinical presentation, imaging findings, diagnostic workup, treatment strategies, and outcomes were analyzed descriptively. Surgical decompression with biopsy was performed in selected patients with rapid neurological deterioration or unclear diagnosis.
Results:
All patients exhibited diffuse enlargement of the cauda equina nerve roots on MRI, although the underlying etiologies were diverse, including malignant lymphoma and immune-mediated neuropathies. In selected cases with diagnostic uncertainty, surgical biopsy provided important pathological information that facilitated a definitive diagnosis and subsequent therapy directed by the diagnosis. Patients with lymphoma generally demonstrated favorable responses to systemic chemotherapy, while those with immune-mediated disorders improved following immunotherapy. Clinical outcomes appeared to vary according to the underlying disease process rather than the extent of radiological abnormalities at presentation.
Conclusion:
Diffuse cauda equina nerve root enlargement represents a radiological pattern associated with heterogeneous etiologies rather than a single disease entity. Careful diagnostic evaluation is required, and surgical biopsy may be helpful in selected cases when noninvasive investigations remain inconclusive.
