Non-Hodgkin's Lymphoma with Intraspinal Involvement Mimics Bilateral Thoracolumbar Plexopath

Non-Hodgkin lymphoma (NHL) is the most common type of lymphoma, and its extranodal manifestation is rare. Skeletal muscle involvement is noted in only 1.1% of patients with NHL. Here, we present a case of high-grade B-cell lymphoma (HGBL); it infiltrated the left neural foramina from the left psoas muscle before encroaching on the whole spinal canal and subsequently invading the contralateral neural foramina from T12 to L3.

A 43-year-old man with HGBL who could function independently presented with numbness and weakness of the left thigh 2 months after a diagnosis of infiltrative lymphoma in the left psoas muscle. His symptoms were urine incontinence and unsteady gait. A neurological examination revealed weakness in the left psoas and quadriceps with hyporeflexia and hypesthesia. Lumbar spine magnetic resonance imaging (MRI) revealed intraspinal extradural invasion from T12 to L3 with multiple left-sided root compression despite the resolution of primary psoas lymphoma. At 6 weeks after symptom onset, his symptoms progressed to weakness, numbness, and hyporeflexia of the bilateral lower extremities with preserved anal sensation. Follow- up MRI revealed the progression of intraspinal invasion, which spread through the spinal canal and invaded the contralateral neural foramina from T12 to L3. The patient was finally bound to a wheelchair.

Clinicians must check for possible intraspinal involvement in patients with HGBL, particularly patients with known paraspinal soft-tissue involvement. The resolved infiltration of the soft tissue does not preclude the possibility of further neurological involvement. Additionally, MRI may provide higher resolution findings for clarifying the structure of the neural foramina and thecal sac. Keyword: Non-Hodgkin's Lymphoma, high-grade B-cell lymphoma, plexopathy.