kPRIMARY ISOLATED AMYLOIDOMA OF THE LUMBAR SPINE CAUSING NEUROLOGICAL COMPROMISE: CASE REPORT AND LITERATURE REVIEW

OBJECTIVE AND IMPORTANCE: We describe a patient with cauda equina compression secondary to amyloidoma to alert other clinicians to this rare cause of a compressive epidural lesion. It is the fourth published report of primary lumbar amyloidoma causing neurological compromise. CLINICAL PRESENTATION: A 53-year-old, previously fit salesman presented with several years history of back pain and recent weakness, especially in the left leg. He also had numbness and tingling radiating down the left leg. On examination, the left knee jerk was diminished, and both ankle jerks were absent. Power was reduced to 4/5 in ankle dorsiflexion bilaterally. A magnetic resonance imaging scan of the lumbar spine revealed an extradural mass, compressing the theca at L3-L4. This was enhancing in T1-weighted images and had low signal intensity in T2-weighted images. There was no evidence of systemic amyloidosis or development of multiple myeloma. INTERVENTION: L3-L4 laminectomy was performed, with removal of the epidural mass. The patient had complete resolution of sciatica and regained normal power in both lower limbs. There was no evidence of any recurrence at 1-year follow-up. CONCLUSION: Lumbar epidural amyloidoma is an extremely rare cause of cauda equina compression. Clinical presentation can be nonspecific, and radiologically, it can be indistinguishable from a tumor. Diagnosis is made at histological examination of a Congo red-stained section under polarized light. Complete resection of the localized epidural amyloid mass is associated with a good prognosis.