Discussion
Diagnosis With Brief Discussion
- Diagnosis
- Necrobiotic (rheumatoid) nodule
- Radiologic Findings
- Fig 1. Chest PA shows a few nodular consolidation in both lung zone. Both CP angles were clear.
Fig 2-6. CT scans reveals multiple low density solid nodules(average HU 40-50) with partial calcification. Enhancement was not evident.
Fig 7-9. After 8 months, size and number of lung nodules slightly increased. Still, there was no evident enhancement of nodules.
- Brief Review
- Rheumatoid nodules are highly specific for RA and occur in 20% of patients, with a predilection in men and patients who smoke cigarettes. Lung nodules are associated with subcutaneous nodules in 80% of cases. The two are histologically identical, demonstrating central fibrinoid necrosis surrounded by palisading epithelioid histiocytes and peripheral chronic inflammatory cells.
Rheumatoid lung nodules at CT are round or lobulated, several millimeters to several centimeters in size, and often peripheral with mid upper lung predominance. They are commonly multiple but may manifest as a single nodule. Calcification can be found. Nodules may increase in size and number, remain stable for years, or resolve spontaneously. Patients are typically asymptomatic but may develop symptoms if nodules cavitate or erode into the pleural space.
Rheumatoid patients with rheumatoid lung nodules are more likely to manifest subcutaneous rheumatoid nodules and seropositivity and tend to be younger than those with malignancy but a history of smoking is common in both groups. When compared to malignancies in the lung, rheumatoid lung nodules appear to have distinctive imaging features including multiplicity, smooth border, satellite nodules, cavitation, and peripheral location with occasionally associated subpleural rind of confluent soft tissue. Rheumatoid lung nodules manifest low to moderate FDG avidity and are not associated with FDG-avid draining lymph nodes.
- References
- 1. Groner, L. K., Green, D. B., Weisman, S. V., Legasto, A. C., Toy, D., Gruden, J. F., & Escalon, J. G. (2021). Thoracic manifestations of rheumatoid arthritis. Radiographics, 41(1), 32-55.
2. Koslow, M., Young, J.R., Yi, E.S. et al. Rheumatoid pulmonary nodules: clinical and imaging features compared with malignancy. Eur Radiol 29, 1684–1692 (2019).
- Keywords