Spinal Rosai-Dorfman disease: Case report of a rare disorder

Background: Rosai-Dorfman disease (sinus histiocytosis with massive lymphadenopathy (SHML)) is a rare, histiocytic, lymphoproliferative disease of unknown etiology affecting young people with male predominance. It is characterized by massive, painless cervical lymphadenopathy with fever and malaise and varying extra-nodal involvement. Isolated spinal canal Rosai-Dorfman disease is extremely rare. We describe a case of isolated Rosai-Dorfman disease with both intradural extramedullary and epidural components. Clinical presentation: 52 year man presented with 2 week history of progressive lower limb weakness and 2 days of urinary and fecal incontinence. He showed bilateral lower limbs weakness with normal muscle tone, exaggerated deep tendon reflexes and no sensory loss. CT and MRI showed large enhancing soft tissue mass lesion with both epidural and intradural extramedullary components opposite to T2-T5 vertebrae causing spinal cord compression associated with marrow changes of the body of T4 vertebra. Intervention: A T3-T5 laminectomy and excision of the epidural lesion was performed. We opened the dura and found a large extramedullary well circumscribed mass engulfing the cord. Careful dissection and total resection of the intradural mass was done. The mass was histopathologically proved to be sinus histiocytosis conforming to Rosai-Dorfman disease. Postoperatively the patient showed improvement in the motor power and regained control over urine and stool. Conclusion: This is a rare case of spinal Rosai-Dorfman Disease with epidural and intradural components causing cord compression. To our knowledge, this represents the first case of combined epidural and intradural extramedullary lesions in the literature.