DISCUSSION: RDD is a rare, non-neoplastic disorder characterized by the proliferation and accumulation of histiocytes most commonly in the lymph nodes of the body, but can also occur in extranodal sites. Although the onset is idiopathic, there has been some literature describing possible links to immune dysfunction, viral infections, such as HHV, parvovirus B19, EBV, and IgG4-related diseases . Signs and symptoms of RDD can vary widely among patients. In most cases of RDD, patient has nonspecific symptoms such as fever, pallor, weight loss, malaise, rhinitis, but it can also present with painless, massive lymphadenopathy, neutrophilia, elevated erythrocyte sedimentation rate, and polyclonal hypergammaglobulinemia . Extranodal manifestations can involve the skin (most common), liver, spleen, CNS involvement, nasal cavity, various bones, and the eyes and eye sockets. The differential diagnosis for RDD is broad including undifferentiated carcinoma, tuberculosis, sarcoidosis, granulomatosis ,melanoma, leukemia, Langherhans histiocytosis, thyroiditis and lymphoma.