Rosai-Dorfman disease isolated to the central nervous system: A report of 11 cases

Sinus histocytosis with massive lymphadenopathy, also known as Rosai-Dorfma n Disease (RDD), is an idiopathic histiocytic proliferation affecting lymph nodes. Although extranodal involvement has been reported in diverse sites, central nervous system (CNS) manifestation, particularly in the absence of nodal disease is uncommon. We report 11 cases of RDD primary to the CNS wi thout evidence of other sites of involvement. The cases included 7 males an d 4 females ranging in age from 22 to 63 years (mean: 41 y), The patients p resented with headaches, seizures, numbness, or paraplegia Eight cases invo lved the cranial cavity and three cases, the spinal canal, Lesions were mos t often extra-axial and dura based. Only one presented in the CNS parenchym a, Histologically, the lesions consisted of variable numbers of pale-staini ng histocytes with emperipolesis often overshadowed by extensive lymphoplas macytic infiltrates and fibrosis in the background. Special stains for orga nisms were negative, By immunohistochemical analysis, the characteristic hi stiocytes were positive for S100 protein and CD68 and negative for CD1a. Tr eatment consisted of surgical biopsy or excision. Follow-up, available for 10 cases with intervals ranging from 5 days to 42 months (mean: 15 mo), dis closed one patient dying of operative complications 5 days after biopsy and nine patients with no evidence of disease progression RDD should be consid ered in the differential diagnosis of inflammatory lesions of the CNS. Our study suggests that this entity may have been misdiagnosed in the past as p lasma cell granuloma or inflammatory pseudotumor.