Lymph node hyalinisation in rheumatoid arthritis and systemic sclerosis.

AIMS To review the histological features of lymph nodes excised from seven patients with rheumatoid arthritis and one with systemic sclerosis. METHODS Lymph nodes excised from seven patients with rheumatoid arthritis and one patient with systemic sclerosis over a 10 year period were examined using the stains haematoxylin and eosin, periodic acid Schiff (PAS), Masson-trichrome, and Congo red for amyloid. RESULTS Of the seven nodes examined from the cases of rheumatoid arthritis, three showed definite reactive follicular hyperplasia with a prominence of plasma cells in the interfollicular areas, two showed subtotal replacement of the node by numerous sarcoid like granulomata, and one contained a large central area of necrosis with a surrounding palisade of histiocytes. In all six cases, focal areas of PAS positive eosinophilic hyaline material were present, which did not stain with Congo red. In some cases this hyaline material was focally calcified. In the seventh patient with rheumatoid arthritis the excised lymph node was almost totally replaced by similar PAS positive hyaline material which showed extensive areas of calcification. The lymph node removed from the patient with systemic sclerosis similarly showed almost total replacement by PAS positive hyaline material. CONCLUSION In all cases the nodes contained PAS positive extracellular hyaline material to a greater or lesser degree. The lymph nodes from two of the patients with rheumatoid arthritis contained numerous sarcoid like granulomata, further indicating a possible association between sarcoidosis and rheumatoid arthritis. Pathologists and clinicians should include rheumatoid arthritis and systemic sclerosis in their differential diagnosis of lymph node hyalinisation of unknown aetiology.