Sinus histiocytosis. Existence in the sinuses of the lymph nodes of abundant histiocytes that contain lymphocytes inside. Hence the inclusion of this disease among histiocytosis . Also known as Rosai-Dorfman disease, they discovered a lymph node condition of unknown etiology characterized by the appearance of large lymphadenopathies , little general condition condition and good prognosis.
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- 1 Etiology
- 2 Pathological anatomy
- 3 Clinical picture
- 4 Laboratory data
- 5 Forecast
- 6 Treatment
- 7 Source
Not known. Although an infectious cause has been suggested, no responsible agent has been identified so far. The association with autoimmunity phenomena and high expression of cytokines (IL-6, IL-1, TNF) has led to suggest that it is due to immune dysregulation.
Macroscopically, the lymph nodes are arranged in masses that have a hard consistency. The cut shows yellowish areas that correspond to the different lymph nodes , surrounded by thick bands of fibrosis. Microscopic examination highlights remarkable capsular and pericapsular fibrosis, often with infiltration of mononucleated cells. The lymphatic sinuses appear distended, full of lymphocytes and abundant histiocytes, with no signs of atypia or clonality. The characteristic feature is the presence of a large number of lymphocytes and even plasma cells inside the histiocytes. Erythrophagocytosis may also be seen. Histiocytes express the beta subunit of the S-100 protein but not CD1a.
The average age of presentation is 20 years, and there is a moderate predominance in males. The most frequent manifestations are fever or low-grade fever and lymphadenopathy. The lymphadenopathies are constantly located in the laterocervical and supraclavicular regions and sometimes invade the submandibular and mental regions, making up a proconsular neck due to their enormous size. Axillary and inguinal lymphadenopathies, when they exist, are usually smaller. In 40% of cases there is extranodal involvement. The affection of the soft tissues of the nasal or periorbital region is characteristic although rare. Less frequently, hepatomegaly, splenomegaly, and a skin rash can be seen.
ESR is usually elevated. Anemia of low intensity is common, as is neutrophilic leukocytosis. Other disorders include hypercholesterolemia, hypertriglyceridaemia, and polyclonal hypergammaglobulinemia. With certain frequency, alterations suggestive of immune dysfunction are detected, such as the presence of autoantibodies, as well as autoimmune hemolytic anemia (5% of cases).
It is usually benign. In 20% of cases the disease remits spontaneously and in half of cases it remains stable without repercussion on the general state. Extranodal involvement with organ dysfunction, together with autoimmune disorders, are the factors associated with an increased risk of progression and evolution, which is occasionally fatal.
In cases with few manifestations, it is best to abstain from any therapy. Only patients in whom a clear progression of the disease is evident should be treated. Despite its wide use, the efficacy of glucocorticoids has not been clearly demonstrated. Some patients have responded favorably to interferon alfa. The efficacy of cytostatics (etoposide, methotrexate, Mercaptopurine ) is limited.