Intravascular large B cell lymphoma (IVBCL) is an aggressive, systemically disseminated, rare subtype of extranodal large B-cell lymphoma confined to the lumen of small- and medium-sized vessels¹. Diversity of presentation, lack of specific laboratory or radiological finding and absence of nodal involvement, poses a diagnostic challenge. Neurological manifestations are frequently observed in western population. CNS involvement is usually preceded by PNS involvement².

We report a female who presented with sign and symptoms of PNS involvement, including intractable radicular pain, moderate motor and sensory loss, along with saddle anesthesia and bladder incontinence. EMG/NCS showed L5/S1 polyradiculopathy. MRI of spine was unremarkable however MRI pelvis showed extensive inflammatory myopathy. MRI changes in gluteal muscles led to muscle biopsy which confirmed the diagnosis of IVBCL. Patient became encephalopathic during admission, MRI brain did not show any etiology except for small lacunar infarct. She was started on Solumedrol, however rapidly deteriorated and passed away.

This case highlights the diagnostic challenges of IVBCL. The presentation was unique in terms of initial features resembling radiculopathy (PNS involvement) followed by rapid deterioration and possible CNS involvement. In a meta-analysis of 645 patients with IVBCL, CNS manifestations like encephalopathy, dementia and stroke were more commonly observed. PNS involvement was rare and mostly seen as myopathy and neuropathies. Tumor infiltration and occlusion of vasa nervosum is considered as a reason for peripheral nerve involvement³. IVBCL presenting as sensorimotor axonal polyradiculopathy diagnosed with muscle and nerve biopsy has been reported. ⁴

Patients presenting with rapidly progressive neurological manifestations or ones that cannot be explained, IVBCL should be suspected. A low threshold for muscle and nerve biopsy should be considered when trying to establish an early diagnosis and treatment.