Diffuse large B-cell lymphoma relapse presenting as extensive neurolymphomatosis.

A 56-year-old woman with a history of diffuse large B-cell non-Hodgkin lymphoma (DLBCL-NHL) in remission for two years presented with weight loss and multifocal sensory/motor symptoms. Magnetic resonance imaging (MRI) of the neuraxis and whole-body FDG PET/CT led to a diagnosis of secondary neurolymphomatosis (NL). MRI demonstrated extensive thickening and enhancement of multiple cranial nerves and peripheral nerve plexuses with corresponding elevated metabolism on FDG PET/CT. Treatment with chemotherapy resulted in complete response on FDG PET/CT and subsequently she underwent autologous stem cell transplantation. NL is a rare manifestation of lymphoma affecting the peripheral nervous system. Nonspecific neuropathic symptoms make clinical diagnosis difficult. Though nerve biopsy is considered the gold standard, MRI and FDG PET/CT are accepted alternatives for making the diagnosis. We review imaging findings in NL, describe the differential diagnosis, and discuss the limitations of the imaging modalities.