Abstract
Introduction Primary neurolymphomatosis is the direct infiltration of lymphomatous neoplastic cells into the nerve roots and/or peripheral nerves and is the first manifestation of an underlying haematological malignancy. The natural history, management and prognosis of the condition are not well understood, given its rarity.
Presentation and Clinical Findings A 67 year old male presented to the emergency department with a 24 month history of progressively worsening, severe neuropathic pain in the left lower limb, weakness of ipsilateral ankle dorsiflexion, and associated gait disturbance.
Diagnosis and Intervention Initial serum biochemistry was unremarkable. A paraneoplastic screen, lymphocyte surface markers, and tumour markers were negative. Cerebrospinal fluid analysis demonstrated raised proteins of 0.69 g/L without neoplastic cells visualised on cytology. Gadolinium enhanced magnetic resonance imaging (MRI) demonstrated thickening and enhancement of the cauda equina, L5, S1 and S2 nerve roots. Marked hypermetabolism within the same nerve root distribution was observed in 18fluorodeoxyglucose (18FDG) positron emission tomography (PET). A biopsy of the L5 nerve root was performed histopathology revealed lymphocytic infiltrate. Immunohistochemistry of the specimen was positive for B-lymphocyte antigen CD20, B-cell lymphoma 2 (Bcl-2) and multiple myeloma 1 (MUM1). These features were consistent with diffuse large B-cell lymphoma (DLBCL).
Outcomes The patient subsequently underwent chemotherapy with R-CHOP, and went into remission following one cycle.
Conclusion Primary neurolymphomatosis presents a diagnostic challenge and as such formal diagnosis is often delayed. Whilst biopsy is the gold standard for diagnosis, gadolinium enhanced MRI and 18FDG-PET are useful in characterising lesions and determining feasibility of biopsy.
