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SynopsisMulticentric reticulohistiocytosis (MRH) is a rare disorder of unknown etiology that primarily affects the skin, mucous membranes, and joints. Typical onset is during the fourth decade of life, but individuals of any age can be affected. There is a predilection for females and people of Northern European descent. Joint involvement precedes cutaneous involvement in just over half of cases, with the onset of skin disease usually occurring 3 years after the onset of arthritis. Joint and skin disease present simultaneously in around one-fifth of patients, and skin disease precedes joint disease in another one-fifth.
In the skin, MRH appears as papules and/or nodules that most frequently occur on the acral areas of the body, especially the head, hands, and juxta-articular regions of the extremities. Mucous membrane involvement occurs in up to half of patients. The typical mucosal eruption is characterized by multiple erythematous papules and nodules that affect the oral and nasopharyngeal mucosa. Mucocutaneous disease typically lasts 5-10 years with subsequent regression.
Joint disease is a prominent feature of MRH that can produce significant morbidity. The typical presentation is a symmetric erosive polyarthritis that may evolve into arthritis mutilans. Progressive destruction of joints occurs in most individuals for about 6-8 years with stabilization thereafter. The distal interphalangeal (DIP) joints are affected most commonly (about 75% of cases), although any joint can be involved.
There are numerous reported associations including malignancy (up to 25%), tuberculosis (12%-50%), autoimmune disorders, and systemic vasculitis. Carcinomas of the lung, breast, stomach, cervix, ovary, and colon are the most frequently associated malignancies, although others have been reported.
E78.81 – Lipoid dermatoarthritis
84241008 – Multicentric reticulohistiocytosis
Differential Diagnosis & Pitfalls
- Rheumatoid arthritis with rheumatoid nodules
- Psoriatic arthritis – Occurs in the setting of psoriasis.
- Reactive arthritis (Reiter syndrome) – Following genitourinary or gastrointestinal tract infection; frequently associated with conjunctivitis, urethritis, enthesitis, and/or mucocutaneous eruption (keratoderma blenorrhagicum and circinate balanitis).
- Gout – Usually asymmetric involvement; gouty tophi can be present.
- Sarcoidosis – Variable clinical presentation, yellow-brown "apple jelly" appearance of lesions on diascopy, frequent lung and eye involvement.
- Papular mucinosis (scleromyxedema) – Characterized by grouped or widespread erythematous papules (large nodules not usually present).
- Progressive nodular histiocytosis – Characterized by widespread nodules that can be quite large in size (up to 5 cm in diameter).
- Erythema elevatum diutinum – Firm, erythematous or violaceous papules and nodules occur over the extensor surfaces, especially around the joints.