High-grade B-cell lymphoma relapse presenting as neurolymphomatosis of the median nerve.

Neurolymphomatosis (NL) is the infiltration of lymphocytes into the peripheral nervous system in a haematological malignancy. We describe the imaging features of NL in a patient with relapsed Burkitt-like non-Hodgkin's lymphoma on positron emission tomography (PET) and ultrasound. Imaging features on ultrasound are infrequently described and provide useful information in helping to establish an imaging diagnosis of NL. Features of NL in our patient included intense linear fluorodeoxyglucose-18 (18FDG) uptake on PET along the affected median nerve. B-mode ultrasound demonstrated concentric tubular thickening and loss of fascicular architecture. Perineural and intraneural vascularity was present on colour Doppler ultrasound. It is important to be able to correlate ultrasound findings to features observed on 18FDG-PET as this aids in diagnosis and in guiding potential surgical biopsy.