Isolated Extradural Rosai-Dorfman Disease of the Thoracic Spine

Abstract

Rosai-Dorfman disease is a rare benign histiocytic disease of unknown origin that arises predominantly in lymph nodes with generalized fever and malaise but can affect a variety of organs. We describe a case of isolated Rosai-Dorfman disease causing thoracic cord compression. A 24-year-old man presented with progressive spastic paraparesis. A magnetic resonance scan revealed an anteriorly placed extradural lesion of the T4-T7 thoracic spine causing cord compression. He was systemically well with no other disease. The patient made a complete recovery after a limited T4-T7 laminectomy and biopsy of the lesion. Repeat magnetic resonance scan at 6 months revealed a further posteriorly placed lesion at the T8/9 level. More extensive posterior surgery was carried out with subtotal resection of the lesion with pedicle screw fixation. Histologically, all specimens revealed fibrous connective tissue infiltrated by histiocytic cells with CD68 and S100 positivity, confirming a diagnosis of Rosai-Dorfman disease. This is a rare case of isolated Rosai-Dorfman disease causing thoracic cord compression. It should be considered among the differential diagnoses of extradural cord compression. Radiological features and treatment options are discussed.