Primary extradural non-hodgkin's lymphoma.

A 67-year-old male presented to our institute with history of paraparesis with decreased sensation and loss of bladder and bowel control. The diagnostic work up revealed an extradural mass at spinal level D7-D12. He had laminectomy and the tumor was sub totally resected. Histological examination revealed non-hodgkin's lymphoma (NHL). The patient was worked up for disease anywhere else in the body and was confirmed to have primary extradural non-hodgkin's lymphoma.

INTRODUCTION

An extradural location of lymphoma is observed in 0.1-6.5% of the cases. No other malignancy is so hetrogeneous and complex in its biological behavior and hightly variable in prognosis as non-hodgkin's lymphoma (NHL). Every year about 367,000 patients are diagnosed to have NHL and extra nodal NHL constitutes about 10-20% of all NHL cases.[1] Spinal cord compression is a rare presentation of NHL occurring only in 0.1-3.3% of patients of primary extradural non-hodgkin's lymphoma (PENHL), However, spinal cord compression may occur in 0.1-10.2% of NHL patients during the course of disease and is usually aggressive in behavior.[2] The clinical feature and outcome of treatment in these patients may vary depending upon the duration of symptoms and time of surgical intervention.

CASE REPORT

A 67-year-old male first presented with back pain and progressive weakness of both lower limbs of 3 months duration with loss of bowel and bladder control since 1 month. On examination, patient was in poor general condition. There was no peripheral lymphadenopathy and was normalon systemic examination. There was a laminectomy scar in dorsal region. Central nervous systemic examination revealed decreased power in both lower limbs with decreased sensation over both feet. Patient was with indwelling Foley's catheter. The whole body positron emission tomography (PET)/CT was performed, which showed an Fluorine18 Fluorodeoxyglucose (FDG) avid soft-tissue lesion in the spinal canal extending from D4 to D12 level causing cord compression [Figure 1]. Whereas, magnetic resonance imaging spine showed a large extradural soft-tissue mass in the spinal canal from D4 to D11/D12 level compromising and deforming cord and causing significant canal stenosis. Bone marrow examination revealed no Infiltration with NHL.

Figure 1

PET computed tomography images show intense FDG uptake in the extradural space of thoracic spine in sagittal (a) coronal, (b) and transverse, (c) planes, (d) PET image in coronal plane

DISCUSSION

Primary spinal epidural lymphoma are tumors with charecteristic histopathological pictures of a lymphoma, which are seen purely in the spinal epidural space, with a negative diagnostic work up for lymphoma in rest of the whole body. Immuno-cytochemical and electron microscopic studies have shown that these tumors most frequently originate from the B-cells.[3] PENHL are seen more commonly in males (66-70%) with a male: female ratio of 1.6:1.0. It usually presents in fourth to fifth decade of life. The most common presenting symptoms are backache and radicular pain of few months with a sudden neurological deterioration. The most common site of involvement is thoracic spine (69%) followed by lumber (27%) and cervical region (4%).[4] The reason for higher percentage of involvement of thoracic spine, is most likely to be the greater length of the thoracic portion as well as more concentration of lymphatic drainage in this region. This is possible due to fewer radicualr arteries to the spinal cord and thus, this region is more susceptible to ischemic injury secondary to epidural compression.[5] The triad of most common presentation in PENHL is weakness of lower limbs (70-92%), localized back pain (50-60%), and bladder dysfunction (28-35%).[6] All patients need a thorough work up like nodal lymphomas to arise at the exact staging and ruling out any other site of primary nodal disease. Plain radiographic abnormalities like pedicle erosion, destruction of vertibral body, and compression fracture and para-spinal mass may be seen in 15-42% of cases.[7] Pathologically most patients have high/intermediate grade histology (4,) some series have reported low-grade histology also. Patients who are seen with spinal cord compression and no known primary lesion elsewhere, require surgical intervention for diagnosis and relief of neurological deficit.[6] As there is mostly absence of bony erosion by these tumors, laminectomy does not jeopardize spinal stability.