Background: In 15-25% of patients with rheumatoid arthritis, the presence of pathognomonic autoantibodies (anti-citrullinated protein (aCCP) or rheumafactor (RF) is lacking. In these cases of seronegative rheumatoid arthritis, diagnosis is based on clinical presentation. However, some of the patients with seronegative rheumatoid arthritis are misdiagnosed.
Case description: Here we discuss a case of a 64 year old female, with a diagnoses of seronegative rheumatoid arthritis for 18 years. Although extensively treated with immunosuppressive medication, she did not reach remission. After second opinion in our hospital we diagnosed Whipple's disease.
Conclusion: This case report illustrates the importance of a broad differential diagnosis of seronegative arthritis as well as the importance of re-assessment of patients diagnosed with seronegative rheumatoid arthritis, who do not reach remission upon immunosuppressive treatment.