What is Sinus Histiocytosis?

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  • Written By: Meg Higa
  • Edited By: A. Joseph
  • Last Modified Date: 27 December 2016
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Sinus histiocytosis is a rare human disorder of unknown cause, usually indicated by the swelling of lymph glands either subcutaneous or in deep tissue. It predominantly affects the young, particularly during the first two decades of life. It usually is benign though sometimes chronic, and in rarer cases, it can metastasize to other parts of the body via the vessels of the lymphatic system. Since first identified in 1969, an effective cure has been elusive, and most physicians recommend close clinical observation without any treatment for the possibility of a spontaneous self-cure.

"Histiocytosis" refers to a class of conditions characterized by the excess production and accumulation of histiocytes, which are normally a beneficial autoimmune macrophage released by the littoral cells that line the inner endothelial wall of lymph nodes. Lymph nodes are small, ball-shaped hollow organs that are distributed throughout the human body’s reticulated immune system. Within the lymph sinuses, immune cells such as histiocytes function as a filter or trap for foreign particles and pathogens. Although inflammation of a lymph node is quite common, particularly when fighting an infection, a disorder of the lymph nodes is called lymphadenopathy.


Sinus histiocytosis with massive lymphadenopathy (SHML) is also called Rosai-Dorfman disease, named after the two collaborating physicians who first described the condition. Most cases occur from birth to age 15 and manifest as large but painless enlargements of the lymph nodes in both sides of the neck, accompanied by fever and other indicators associated with infection. A biopsy will confirm overactive littoral cells, distended sinus channels and an elevated histiocyte count. If there is additional evidence of dermatopathy, or an aberrant skin condition, histiocytes are likely to have escaped the confines of the lymph node and begun attacking surrounding skin cells.

A sinus histiocytosis that has spread to sites other than the lymph nodes is described as extranodal, and it occurs in about one-fourth of all cases. The skin, bone and the upper respiratory tract are common destinations, but an extranodal metastasis can strike anywhere in the body, including the central nervous system, the genitourinary system and the breasts. Treatment and recovery might take years or decades depending on the number of lymph nodes and the type of extranodal organs affected by SHML. Meanwhile, patients are further at risk of exposure to their compromised immune system. Some physicians therefore prefer aggressive therapies for this disease.

The etiology, or cause, of sinus histiocytosis is unknown. DNA studies of the offending histiocytes have found no evidence of change, suggesting that the disease is a reactive condition, possibly in response to a yet undiscovered virus. The fact that it usually follows a benign clinical course, often with spontaneous resolution and little if any lasting ill effects, supports this theory. On the other hand, especially in extranodal cases, the disease behaves not unlike malignant cancers, including periods of exacerbation and remission. Corresponding therapies — surgical excision of lymph nodes, chemotherapy and radiation — have had inconsistent degrees of efficacy.


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Post 1

this is a very good piece of knowledge but i think treatment options should be given so people can get benefit from that.

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