Cytophagic histiocytic panniculitis
What is cytophagic histiocytic panniculitis?
Cytophagic histiocytic panniculitis is a condition of the subcutaneous fat where there is an infiltrate of histiocytes and inflammatory cells leading to breakdown and hemorrhage in the fat. The histiocytes tend to engulf other cells, including red cells, white cells and particulate matter. The histiocytes in cytophagic histiocytic panniculitis are not malignant. Histiocytes are cells which have a phagocytic function i.e. they can engulf particulate matter. The term cytophagic refers to cells which engulf other cells. Panniculitis refers to a disorder of the subcutaneous fat.
Phagocytosis of cells by histiocytes, with resulting tissue damage, affects other organs as well as the skin.
What are the symptoms of cytophagic histiocytic panniculitis?
In cytophagic histiocytic panniculitis painful subcutaneous nodules develop at multiple sites. The patient feels unwell and has a fever. Enlargement of the liver and spleen, a decrease in the cells and platelets in the blood and progressive liver failure develop. Death when it occurs is associated with bleeding from the gastrointestinal, urinary and respiratory tracts and into the skin. There is liver failure and jaundice.
What is the cause of cytophagic histiocytic panniculitis?
In more than half of cases, cytophagic histiocytic panniculitis is triggered by an infection (mainly a viral infection from the herpes-virus family) in a patient with altered immune function (immunodeficiency, autoimmune disease, hematological disease). A subcutaneous T-cell lymphoma should be searched for in all cases but is a diagnostic challenge. Such lymphomas are associated with histologic features of cytophagic histiocytic panniculitis.
What investigations should be done?
Biopsy of a subcutaneous nodule shows the pathologic changes of cytophagic histiocytic panniculitis. Blood tests may show damage in other organs and a bleeding tendency. There may be evidence of a preceding infection such as with the herpes virus group and of altered immune function. If there is an associated T cell lymphoma special DNA tests may be positive for this.
The disease is usually lethal if untreated. Any causative factors should be treated where possible. Symptomatic treatment consists of transfusion and corticosteroid therapy. Etoposide and ciclosporin have been reported to be helpful in some cases. Some authors recommend that cytophagic histiocytic panniculitis should be treated with CHOP-like polychemotherapy. Good results have been obtained with high dose intravenous immunoglobulin. If a subcutaneous T cell lymphoma is also present treatment will need to be modified accordingly.