br Discussion The onset of

Discussion The onset of disease is deceptive; its active phase seems to be prolonged and its remission may be spontaneous with possibility recurrence [3]. The factors that determine recurrences are not well understood. The predominant clinical manifestation of the disease is tumoral cervical adenopathy (87.3% of cases) that, in most cases, is painless and bilateral, affecting one or all cervical chains. The neck BI6727 nodes are the most frequently involved, followed by inguinal, axillary and mediastinal lymph nodes [4]. Lymph nodes are isolated, mobile, and small during the initial stages but become adherent with disease progression, forming a voluminous multinodular mass. The most common extra nodal sites are the skin, the upper respiratory tract and bones. Head and neck involvement - about 22% of extra nodal disease [5] include involvement of the nasal cavity, the paranasal sinuses, the nasopharynx, submandibular glands, the parotid, the larynx, the temporal bone, the intratemporal fossa, the pterygoid fossa, the meninges and the orbit [6]. The skin is commonly affected; half of these patients have another associated extra nodal site. Orbit and ocular globe involvement have been reported, usually as a retro arbitrary mass and proptosis [7]. although nodal involvement may have occurred during an earlier phase. Fever occurs in up to 30% of cases but was absent in our patient. In 85% of cases, patients with Rosai-Dorfman disease are in good general health without significant symptoms of the disease [8]. Laboratory alterations are frequent and include anaemia (65.7%), leucocytosis (59.1%), neutrophilia (68.4%), increased ESR (88.5%), and hyper-gamma-globulinemia (90%) [1,2], which was similar to the laboratory results in our case. The cause of the disease has not yet been established [9], but two theories exist. In the first theory, SHML is caused by a specific infectious process as Epstein Bar Virus and human Herpes viruses, which have been isolated in some patients [11], based on the generally infectious process seen at the onset of the disease (localized adenopathy, fever, leucocytosis with neutrophilia, increased erythrocyte sedimentation rate, and hyper-gamma-globulinemia), which tends to spontaneously regress after some time. However, no laboratory evidence points to an etiologic agent). In the second theory, the disease is attributed to an abnormal immunologic response, because depression of immunologic cells can be observed. Rosai-Dorfman disease is an entity that is part of a group of systemic disorders, which share numerous anatomic, histological and pathophysiologic features. Therefore, a differential diagnosis of RDD should be excluded from xantho-granulomatous disease. B-cell lymphoma and benign lymphoid hyperplasia [1]. Other disorders that may superficially resemble RDD include Burkitt\'s lymphoma, rhabdomyosarcoma, granulocytic sarcoma, neuroblastoma and Langerhans cell histiocytosis. The differential diagnosis of Rosai-Dorfman is made following a biopsy of the affected tissue. A small piece of the tissue is obtained so that it can be viewed under a microscope by a pathologist, if the cells in the tissue have certain specific characteristics, the diagnosis of RDD can be made. This procedure can be performed of the lymph nodes. skin, bone, liver, lung, or bone marrow. RDD cells stain with S100 protein and CD68 [3,10]. In histological examination the histiocytes in RDD, Langerhans cell histiocytosis, and other histiocytosis express the S-100 protein, (a neural tissue-specific protein) however; the pathophysiology of this S-100 expression remains obscure. Although positive staining for S-100 strongly suggests RDD, it is not absolutely required to make the diagnosis in the presence of typical histology of RDD [7]. The disease is classically described to have an indolent, self-limiting course however; this is not always the case.