Primary Neurolymphomatosis Presenting with Polyradiculoneuropathy Affecting One Lower Limb

We report a case of primary neurolymphomatosis (NL) with unusual presentation and excellent treatment response. Methods: Chart review. Results: A 64-year-old woman presented with 2 months of progressive pain, weakness, and numbness in her right leg. Nerve conduction study/electromyogram suggested a right lumbosacral radiculoplexus neuropathy with associated acute right peroneal neuropathy at the fibular head. L/S spine and right leg magnetic resonance imaging showed thickening and contrast enhancement of the right S1 nerve root and the right distal sciatic, tibial, and common peroneal nerves, as well as a lobular enhancing lesion of the right superficial peroneal nerve. Whole-body fludeoxyglucose-positron emission tomography scan showed no other lesions. A right superficial peroneal nerve lesion biopsy revealed infiltration of the nerve by diffuse large B-cell lymphoma. The lymphoma cells expressed BCL2 but not CD10, suggesting an origin in peripheral blood not lymph nodes. Despite the expression of BCL2, which is considered as a poor prognosis marker, our patient responded very well to the combined radiotherapy and chemotherapy with the R-MPV (rituximab, MTX, procarbazine, and vincristine) regimen. The patient showed marked clinical improvement and complete resolution of lymphoma lesions on the PET scan. Conclusions: Our case broadens the clinical spectrum and illustrates the importance of early diagnosis and aggressive treatment of primary NL.