Case Presentation: A 30-year-old African American man with no prior medical history presented with two weeks of sharp lower back pain radiating to the left flank and leg with associated tingling. He also reported night sweats, chills, and subjective fevers during this time. He denied recent weight loss, bowel and bladder dysfunction, IV drug use, and any proceeding trauma.
On admission, physical examination revealed point tenderness over the lumbar spine without focal neurologic deficits, lower extremity weakness, or saddle anesthesia. His pain radiated below the knee, and straight leg raise did not illicit pain. Aside from a mildly elevated c-reactive protein (4.08 mg/dL) and sedimentation rate (27 mm/Hr), laboratory examination was unremarkable. Computed tomography (CT) of abdomen/pelvis with intravenous (IV) contrast depicted bilateral hypodense renal lesions and spinal mottling. Magnetic resonance imaging (MRI) of the cervical, thoracic, and lumbar spine was obtained due to concern for underlying spinal cord involvement. This revealed severe cauda equina compression at L3 secondary to an enhancing paraspinal mass extending from L2 to L4. The patient was diagnosed with cauda equina syndrome, surgery was consulted, and he was started on IV dexamethasone with gradual improvement in his symptoms. CT-guided biopsy of a renal mass showed T cell/histiocyte-rich large B-cell lymphoma (T/HLBCL). The patient was subsequently discharged with emergent radiation-oncology and hematology follow up.
Discussion: T/HLBCL is extremely rare, accounting for less than 3% of all diffuse large B-cell lymphomas. The diagnosis is made histologically with less than 10% malignant B cells seen among a background of reactive T cells and histiocytes. If present, extranodal involvement usually occurs in the gastrointestinal system. To our knowledge, renal involvement has never been reported – this may represent the first documented case of renal T/HLBCL. Furthermore, there are only a few reports of cauda equina syndrome secondary to T/HLBCL. This case represents a unique presentation of T/HLBCL with both renal involvement and cauda equina syndrome.
In addition to its uncommon presentation of a lymphoma, this case demonstrates an important teaching lesson for clinicians. It highlights the utility of a thorough history and physical examination to aid in diagnosis. As demonstrated, the patient’s lower back pain could have easily been attributed to sciatica or lumbar strain given his age and a fairly unremarkable laboratory work-up. Importantly, the presence of B symptoms and point tenderness of the lumbar spine triggered the pursuit of advanced imaging, leading to the diagnosis and treatment of an emergent medical condition.
Conclusions: Renal involvement and cauda equina syndrome are a rare presentation of T/HLBCL. Physicians should have a low threshold to utilize imaging in the evaluation of even young, otherwise healthy patients with constitutional symptoms or a suggestive physical exam given the concern for an underlying malignant process.