Granulomatous tophaceous gout mimicking tuberculous tenosynovitis: report of two cases.

Granulomatous inflammation in a tissue specimen raises concern about infection with Mycobacterium tuberculosis, atypical mycobacteria, certain fungi, Brucella species, and other infectious agents. Inflammatory disorders, such as sarcoidosis, crystal-associated arthritis, or foreign body reactions also are considered when granulomatous changes are seen on histological examination of a tissue specimen. We describe two cases of granulomatous tenosynovitis due to tophaceous deposits in patients with gout. In one case, tuberculous synovitis was considered the primary diagnosis until the diagnosis of gout was confirmed by examination of a tissue specimen with polarized light. In the second case, gout and tuberculosis were found in the patient's wrist joint. After antituberculous therapy was discontinued, he continued to have wrist synovitis and chronic drainage due to granulomatous tophaceous gout. The findings in this report suggest that gouty tenosynovitis can mimic tuberculous tenosynovitis and that gout should be considered in the differential diagnosis of granulomatous tenosynovitis, especially when acid-fast stains and cultures are negative for mycobacteria.