Intravascular large B-cell lymphoma (IVLBCL) is a rare malignancy characterized by the proliferation of lymphoma cells in blood vessels. Luminal occlusion results in ischemia, producing varied systemic and/or neurological symptoms. Here, we present a patient with IVLBCL who first presented with cauda equina syndrome.

A 69-year-old man presented with a five-week history of lumbosacral pain, bilateral leg weakness and numbness, saddle anesthesia, and bowel and bladder incontinence. MRI lumbar spine showed cauda equina enhancement, and CSF studies demonstrated 5 nucleated cells, protein 182 mg/dL, normal glucose, and negative cytology. The patient’s leg weakness and numbness worsened and repeat MRIs showed continued cauda equina and left sciatic nerve enhancement as well as muscle edema and enhancement involving the bilateral thigh adductors and left gluteus maximus. EMG showed evidence of a severe lumbosacral polyradiculoneuropathy.  Patient was treated with IV steroids and plasmapheresis without improvement. He then developed left amaurosis fugax, and MRI brain revealed multiple small subacute strokes within the cerebral hemispheres and cerebellum. One month later, he developed monocular vision loss in the right eye, and repeat MRI brain showed interval progression of acute and subacute infarcts involving multiple vascular territories. Cerebral and spinal DSAs showed no evidence of vasculitis. Given his continued clinical progression and elevated serum LDH levels (342-565 U/L), CSF cytology and flow cytometry were repeated and again came back negative. Random telescoping skin biopsies were similarly unremarkable. Neurosurgery was consulted for lesional brain biopsy of the right frontal lobe, which confirmed the diagnosis of IVLBCL.

In review of the literature, cauda equina syndrome is a rare presenting manifestation of IVLBCL, where diagnosis was made post-mortem in roughly half of the cases. Clinicians should remain suspicious of IVLBCL masquerading as unusual clinical phenotypes, particularly in patients with rapidly progressive central or peripheral neurological deficits.