Multicentric ReticulohisotiocytosisDz

Synonyms: Lipoid dermatoarthritis, normocholesterolemic xanthomatosis.

ICD-9 Code: 272.8.

Definition: Multicentric reticulohistiocytosis is a rare disorder characterized by infiltration of lipid-laden histiocytes into various tissues. The typical clinical picture includes skin nodules and a chronic destructive polyarthritis.

Etiology: Although the cause is unknown, infectious agents such as mycobacteria have been suspected as an etiologic agent; none has been conclusively implicated. There are no known genetic associations.

Pathology: Multicentric reticulohistiocytosis is characterized by accumulation of histiocytes and multinucleated giant cells at affected sites.

Demographics: Multicentric reticulohistiocytosis is a rare disorder that is seen in middle-aged women more frequently than children.

Cardinal Findings: Multicentric reticulohistiocytosis often presents with a chronic, symmetric, polyarthritis affecting the proximal or distal interphalangeal joints of the hands and may be associated with joint destruction, particularly of the distal interphalangeal joints. Less commonly involved joints include the shoulders, knees, wrists, and hips. The skin nodules over the hands and elbows resemble rheumatoid nodules. Nodules may also occur on the ears, chest, face, and mucosal surfaces (e.g., lips, tongue, gingiva). Other skin lesions seen in multicentric reticulohistiocytosis (but not typical of RA) include small papules that occur in bead-like clusters about the nailfolds and xanthelasma.

Complications: A minority may be tuberculin positive or have an associated malignancy.

Diagnostic Tests: Less than one-third of patients have an elevated ESR or hypercholesterolemia. Patients are seronegative for RF and ANA. Synovial fluid findings are variable and may reveal inflammatory or noninflammatory fluid.

Keys to Diagnosis: The diagnosis of multicentric reticulohistiocytosis is made by biopsy of the affected synovium or skin lesions. Multinucleated giant cells in these lesions characteristically contain large amounts of periodic acid–Schiff staining material, indicating lipid accumulation. There are no diagnostic laboratory tests. Multicentric reticulohistiocytosis needs to be distinguished from RA and other chronic inflammatory arthritides such as psoriatic arthritis.

Therapy: Therapeutic agents that have been used for this disorder include corticosteroids and cytotoxic drugs such as cyclophosphamide. The small number of affected patients precludes large therapeutic trials. Although spontaneous remission has been reported, particularly among children, the disease in most patients has a progressive course.

BIBLIOGRAPHY

Santilli D. Multicentric reticulohistiocytosis: a rare cause of erosive arthropathy of the distal interphalangeal finger joints. Ann Rheum Dis 2002;61:485–487.PMID:12006317