Rheumatoid pseudotumor of urinary bladder simulating carcinoma.

A forty-nine-year-old female with seropositive rheumatoid arthritis was seen with hematuria and a urinary bladder lesion which on cystoscopic examination simulated carcinoma. Microscopic evaluation after segmental resection of the lesion revealed that it was a rheumatoid nodule. Rheumatoid nodules are known to occur in many parts of the body, but an extensive search of the literature has failed to reveal any previous report of urinary bladder involvement.