What is the definition of Multicentric Reticulohistiocytosis?
Multicentric reticulohistiocytosis is a disease that is characterized by the presence of papules and nodules and associated with arthritis mutilans. The disease can involve the skin, the bones, the tendons, the muscles, the joints, and nearly any other organ (e.g., eyes, larynx, thyroid, salivary glands, bone marrow, heart, lung, kidney, liver, gastrointestinal tract). In the majority of cases, the cause of multicentric reticulohistiocytosis is unknown; however, it has been associated with an underlying cancer in about one fourth of cases, suggesting that it may be a paraneoplastic syndrome.
What are the symptoms for Multicentric Reticulohistiocytosis?
The main symptoms of multicentric reticulohistiocytosis are arthritis and red to purple skin nodules varying in size from 1 to 10 mm. The nodules can be found on any part of the body but tend to concentrate on the face and hands and decrease in number from head to toe. The arthritis is most often symmetrical and polyarticular (affecting many joints). Unlike adult rheumatoid arthritis, it does not spare the joints closest to the fingertips. It can be severely destructive, and in one third of cases it progresses to arthritis multilans. Further history reveals that approximately one third of patients complain of symptoms such as fever, weight loss, and malaise; less often, pericarditis and myositis are present.
The clinical presentation of multicentric reticulohistiocytosis is insidious in onset and begins with arthritic complaints in approximately two thirds of patients. It is potentially one of the most rapidly destructive forms of arthritis. Joint involvement remits and relapses, gradually worsening into a debilitating and permanent arthritis multilans. The severity of the damage has been reported to be related to the age of onset; therefore, the earlier one has symptoms, the more severe the symptoms tend to be. Like the associated arthritis, skin lesions tend to wax and wane until the disease spontaneously resolves, but may leave permanent disfigurement.
What are the current treatments for Multicentric Reticulohistiocytosis?
Dermatologists and rheumatologists are often the types of specialists that oversee the treatment of patients with multicentric reticulohistiocytosis. Although no specific therapy has consistently been shown to improve multicentric reticulohistiocytosis, many different drugs have been used. For instance, therapy with non-steroidal anti-inflammatory agents (e.g., aspirin or ibuprofen) may help the arthritis. Systemic corticosteroids and/or cytotoxic agents, particularly cyclophosphamide, chlorambucil, or methotrexate, may affect the inflammatory response, prevent further joint destruction, and cause skin lesions to regress. Antimalarials (e.g., hydroxychloroquine and mefloquine) have also been used. Alendronate and other bisphosphonates have been reported to be effective in at least one patient and etanercept and infliximab have been effective in some.
What is the outlook (prognosis) for Multicentric Reticulohistiocytosis?
After an average course of 8 years, patients often go into remission (a state where symptoms have subsided). The disease can cause considerable morbidity (disability as a result of the disease), mainly related to the occurrence of severe arthritis. The arthritis can come and go, but it can be very severe in about 45% of cases. If the patient has an associated cancer, the prognosis relates to that of the specific cancer.