Multicentric reticulohistiocytosis (MRH) is a rare disorder that is poorly understood. It recently has been shown to respond to targeted therapy against tumor necrosis factors alpha (TNF-alpha).


Clinical findings:

(1) multiple papulonodular skin lesions

(2) erosive symmetrical polyarthritis with progressive articular destruction

(3) variable involvement of mucosa and internal organs


For some patients MRH may occur as a paraneoplastic skin disorder.


Clinical course:

(1) The mean duration of disease activity is about 8 years.

(2) Disability associated with the polyarthritis may be significant.


Differential diagnosis:

(1) rheumatoid arthritis (RA)


Pathologic findings in a biopsy from a skin lesion or affected synovium:

(1) admixture of large mononuclear cells:and multinucleated giants cells

(2) cells have a PAS-positive ground glass cytoplasm with variable inclusions

(3) background of fibrous tissue

(4) variable lymphoplasmacytic infiltrate



(1) vimentin positive

(2) mononuclear cells positive for Factor XIIIa

(3) multinucleated giant cells positive for CD68, lysozyme and HLA-DR.


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