Demonstration of peripheral nerve root involvement by non-Hodgkin’s lymphoma on ¹⁸F-FDG PET/CT

Excerpt

We present images obtained during whole-body ¹⁸F-fluorodeoxyglucose (FDG) positron emission tomography (PET)/CT requested for evaluation of extent of disease in a 66-year-old man diagnosed with non-Hodgkin’s lymphoma (NHL). The patient presented 20 months prior to the scan with bilateral lower extremity paresthesia and weakness, eventually progressing to paraplegia, and initially treated for inflammatory neuropathy. After an extended workup, including multiple lumbar punctures, flow cytometry from cells found in the central nervous system (CNS) fluid revealed CD10+ B-cell NHL. Lymphoma has been described as the Great Mimicker [1, 2] in clinical practice and in imaging for its protean manifestations and inclusion in many differential diagnoses. Here we present a case of CNS lymphoma with striking peripheral perineural involvement. The maximum intensity projection image (a) from ¹⁸F-FDG PET/CT shows extensive and diffuse involvement of multiple peripheral nerve roots, including cervical nerves extending from the right C1/C2 level, the brachial plexus, and lumbosacral nerve roots forming the lumbosacral plexus bilaterally, continuing into the femoral and sciatic nerves. Transaxial CT (b), PET (c), and fused PET/CT (d) demonstrate increased ¹⁸F-FDG uptake in diffusely enlarged nerve roots at several levels. While ¹⁸F-FDG PET/CT is used extensively in the management of NHL [3, 4], such extensive peripheral nerve root involvement present on ¹⁸F-FDG PET/CT is not described in the literature.

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