Lumbosacral Plexus Neurolymphomatosis: A Typical 18FDG PET/CT Pattern to Recognize

Area of Science:

• Oncology
• Neurology
• Nuclear Medicine

Background:

• Primary central nervous system diffuse large B-cell lymphoma (CNS-DLBCL) is a rare and aggressive non-Hodgkin lymphoma.
• Immunochemotherapy followed by MRI complete response is a standard treatment approach.
• Persistent radicular pain can be a challenging symptom in post-treatment lymphoma patients.

Observation:

• A 79-year-old male with a history of CNS-DLBCL presented with chronic right-sided lumbosacral radicular pain.
• Standard diagnostic workup including MRI and cerebrospinal fluid cytology was negative.
• 18FDG PET/CT demonstrated intense tracer uptake in the lumbosacral plexus roots.

Findings:

• The observed 18FDG uptake pattern was highly suggestive of peripheral neurolymphomatosis relapse.
• This finding indicates a recurrence of lymphoma involving the peripheral nervous system.
• The patient's rapid decline in performance status precluded further treatment.

Implications:

• 18FDG PET/CT is a valuable tool for diagnosing neurolymphomatosis relapse in patients with CNS-DLBCL.
• Peripheral neurolymphomatosis can manifest as radicular pain and may be missed by conventional imaging.
• Early detection and appropriate management of neurolymphomatosis are crucial for improving patient outcomes.