Rosai-Dorfman disease of vertebra: Case report and literature review.

Rosai-Dorfman disease is a rare benign histiocytic disorder that arises predominantly in lymph nodes with fever and malaise, but can affect various organs, with or without lymphadenopathy. Solitary extranodal skeletal lesions are extremely rare. Herein, we describe a case of isolated disease of thoracic spine, with vertebral body fracture. A 14-year-old girl presented with cervical back pain for about one month as the only symptom. There was no lymphadenopathy. Results of laboratory tests were within reference ranges. The radiological examinations revealed collapse, osteolytic lesion and compressive fracture, which reduced vertical diameter of C4 vertebral body. The patient made a complete recovery after a limited C4 laminectomy, spondylodesis C3/C5 vertebra and biopsy of the lesion. Histologically, nonspecific cellular milieu and atypical histiocytic proliferation with emperipolesis, with CD68 and S100 positivity, confirmed a diagnosis of Rosai-Dorfman disease. Isolated extranodal skeletal Rosai-Dorfman disease should be considered among the differential diagnoses of similar changes, such as Langerhans cell histiocytosis, Erdheim-Cheister disease, eosinophilic granuloma, osteomyelitis, metastasis and lymphoma.