Mediastinal and axillar lymphadenopathy in patients with rheumatoid arthritis: prevalence and clinical significance.

BACKGROUND: With recent advances of biological disease-modifying antirheumatic drugs, chest CT has been increasingly performed in rheumatoid arthritis (RA) patients, and mediastinal/axillar lymphadenopathy is being detected.

PURPOSE: To determine the prevalence of mediastinal and axillar lymph node enlargements on chest CT in RA patients at the initial diagnosis, and to assess its clinical significance.

MATERIAL AND METHODS: We retrospectively reviewed the medical records and chest CT findings of 78 consecutive RA patients. The short axis of the most enlarged lymph nodes (SLN) on CT was measured for the mediastinal and axillar regions separately. The SLN was classified into two groups: Group 1, 10 mm or less; and Group 2, larger than 10 mm.

RESULTS: Group 2 was observed in 13 of 78 patients (17%) for the mediastinum, and in 29 (37%) for the axilla; 11 patients (14%) showed Group 2 for both regions. The Group 2 patients (n = 31), either mediastinum or axilla, showed significantly higher simple disease activity index (SDAI) (mean, 36.0) than the patients of Group 1 (n = 47; mean SDAI, 23.0) (p < 0.001). For the mediastinal SLN, the RA-related lung disease was more frequently observed in the Group 2 patients than in the Group 1 (p = 0.036).

CONCLUSION: The mediastinal and/or axillar lymphadenopathy on chest CT may reflect the activity of RA. The mediastinal lymphadenopathy also seems to relate to the RA-related lung disease.