Sinus histiocytosis with massive lymphadenopathy (Rosai-Dorfman's disease) previously misdiagnosed as Toxoplasma Lymphadenitis.

Here we describe a case of Rosai-Dorfman Disease (RDD) in a 25-year-old female patient from Turkey who was previously misdiagnosed with Toxoplasma Lymphadenitis, and review the manifestations and treatment of this rare entity. To the best of our knowledge this is the third description of RDD [Sinus Histiocytosis with Massive Lymphadenopathy (SHML)], involving bilateral cervical lymphadenopathy and nephromegaly previously misdiagnosed as Toxoplasma Lymphadenitis. Representative clinical, radiographic and histological findings are presented. Its etiology, diagnosis and management are also reviewed. Sinus Histiocytosis with Massive Lymphadenopathy is a rare disorder of unknown etiology, usually associated with lymph node enlargement in various superficial or deep sites. The key histologic feature of SHML is the presence of various numbers of large, pale histiocytic cells that contain within their cellular borders apparently engulfed lymphocytes (emperipolesis); these distinctive large, pale cells are S-100 protein positive CD-68 positive and CD1a negative by immunostaining. According to the literature the most effective treatment found was surgical debulking.