Sciatic nerve neurolymphomatosis - extent and therapy response assessment with PET/CT.

Neurolymphomatosis is a rare condition and may be the first and only manifestation of a non-Hodgkin lymphoma. We present the case of a 59-year-old patient with fluctuating gluteal pain for 5 years and progressive palsy of the left lower extremity, leading to severe walking difficulties. The neurologic examination revealed pronounced atrophy, flaccid paresis, and sensory loss in the area of innervation of the left sciatic nerve. Electroneuromyography showed a severe sensomotoric axonal lesion of the left sciatic nerve. Biopsy of the lesion revealed diffuse large B-cell lymphoma. Fluorodeoxyglucose (FDG)-positron emission tomography/computed tomography was performed for staging, showing a high FDG uptake of the left sciatic nerve. FDG-positron emission tomography/computed tomography after six cycles of chemotherapy showed complete metabolic response.