Diagnosis of neurolymphomatosis with FDG PET

Neurolymphomatosis (NL) is a rare condition caused by intraneural infiltration of malignant lymphocytes in peripheral nerves. Clinically, NL is characterized by a progressive and painful axonal polyneuropathy. It may develop in patients with widespread non-Hodgkin lymphoma (NHL) but may also be the first manifestation or sole relapse site of NHL. In 50% of cases, it is associated with leptomeningeal involvement. The diagnosis has to be confirmed by biopsy of an affected nerve showing lymphomatous infiltration; however, this may not be feasible or nondiagnostic. We present a case that shows the value of [18F]fluorodeoxyglucose (FDG) PET in such cases.1 In March 2001, a 57-year-old woman presented with progressive paresis of the left and right arm, with radicular pain radiating to the left thumb. Her medical history revealed a swelling of the left orbit in 1998, diagnosed elsewhere as a possible low-grade NHL, which had been treated with radiotherapy. At neurologic examination, there was atrophy of the left trapezius and deltoid muscles, with a paralysis and areflexia of the left arm and a mild paresis …