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February, 2025
Case of the Month
Clinical History: A middle-aged man with a history of rheumatoid arthritis presented with multiple cavitary nodules and a spontaneous pneumothorax. Given the radiologic concern for malignancy and persistent air leaks, the patient underwent multiple lung wedge biopsies from the upper and lower lobes.
Q1. 1. Which of the following histologic features is characteristic of pulmonary rheumatoid nodules?
- Caseating necrosis surrounded by Langhans giant cells
- Central fibrinoid necrosis with palisading histiocytes
- Granulomatous inflammation with asteroid bodies
- Dense neutrophilic infiltrate with abscess formation
Q2. What is a common complication associated with cavitary rheumatoid nodules?
- Carcinoma
- Pulmonary embolism
- Pneumothorax
- Tracheal stenosis
Q3. 3. Which of the following best characterizes the most common radiologic appearance of pulmonary rheumatoid nodules?
- A solitary, centrally located nodule with spiculated margins
- Multiple, well-circumscribed, subpleural nodules that may occasionally cavitate
- Diffuse, ill-defined ground-glass opacities throughout both lungs
- A reticulonodular pattern with interstitial thickening predominantly in the lower lobes
Answers to Quiz
Q1. B
Q2. C
Q3. B
Q2. C
Q3. B
Diagnosis
Pulmonary rheumatoid nodules
Discussion
The lung wedge resections demonstrate characteristic histologic features of pulmonary rheumatoid nodules. A thickened pleural rind is present with areas of fibrinous necrosis and palisading histiocytes. Lymphoid aggregates are evident, composed of intermixed CD20-positive B cells and CD3-positive T cells. The central regions of the nodules exhibit eosinophilic fibrinoid necrosis with a necrobiotic character, surrounded by peripheral basophilic karyorrhectic debris, which is an important diagnostic feature.
Rheumatoid arthritis is a chronic inflammatory disease that can involve the lungs in various forms, including pleural effusions, interstitial lung disease, and pulmonary nodules. Rheumatoid nodules in the lung are rare and most commonly subpleural or pleural-based, typically affecting the periphery of the upper and middle lung zones. Cavitation is observed in up to 50% of cases and may predispose to complications such as pneumothorax, pleural effusion, and bronchopleural fistula. In this patient, multiple cavitary rheumatoid nodules likely led to pneumothorax, a recognized but uncommon complication.
Histologically, pulmonary rheumatoid nodules resemble their subcutaneous counterparts, featuring a central zone of fibrinoid necrosis with surrounding palisading histiocytes and an outer lymphocytic infiltrate.
A proportion of patients with rheumatoid arthritis can develop interstitial lung disease (RA-ILD), with usual interstitial pneumonia (UIP) being the most common subtype. In this case, no features of underlying ILD were present.
Clinically, rheumatoid lung nodules are usually asymptomatic but can lead to significant complications such as pneumothorax, bronchopleural fistula, and hemoptysis. Smoking and methotrexate therapy are known risk factors for nodule development. Given their radiologic overlap with malignancy, histologic confirmation is often necessary to establish a diagnosis. The natural course of these nodules is variable, with some resolving spontaneously while others persist or progress.
Take home message for trainees:
Consider pulmonary rheumatoid nodules in the differential diagnosis of cavitary lung nodules, particularly in patients with rheumatoid arthritis.
Rheumatoid arthritis is a chronic inflammatory disease that can involve the lungs in various forms, including pleural effusions, interstitial lung disease, and pulmonary nodules. Rheumatoid nodules in the lung are rare and most commonly subpleural or pleural-based, typically affecting the periphery of the upper and middle lung zones. Cavitation is observed in up to 50% of cases and may predispose to complications such as pneumothorax, pleural effusion, and bronchopleural fistula. In this patient, multiple cavitary rheumatoid nodules likely led to pneumothorax, a recognized but uncommon complication.
Histologically, pulmonary rheumatoid nodules resemble their subcutaneous counterparts, featuring a central zone of fibrinoid necrosis with surrounding palisading histiocytes and an outer lymphocytic infiltrate.
A proportion of patients with rheumatoid arthritis can develop interstitial lung disease (RA-ILD), with usual interstitial pneumonia (UIP) being the most common subtype. In this case, no features of underlying ILD were present.
Clinically, rheumatoid lung nodules are usually asymptomatic but can lead to significant complications such as pneumothorax, bronchopleural fistula, and hemoptysis. Smoking and methotrexate therapy are known risk factors for nodule development. Given their radiologic overlap with malignancy, histologic confirmation is often necessary to establish a diagnosis. The natural course of these nodules is variable, with some resolving spontaneously while others persist or progress.
Take home message for trainees:
Consider pulmonary rheumatoid nodules in the differential diagnosis of cavitary lung nodules, particularly in patients with rheumatoid arthritis.
References
Alunno A, Gerli R, Giacomelli R, Carubbi F. Clinical, epidemiological, and histopathological features of respiratory involvement in rheumatoid arthritis. Biomed Res Int 2017;2017:7915340.
Sagdeo P, Gattimallanahali Y, Kakade G, Canchi B. Rheumatoid lung nodule. BMJ Case Rep 2015;2015:bcr2015213083.
Koslow M, Young JR, Yi ES, Baqir M, Decker PA, Johnson GB, Ryu JH. Rheumatoid pulmonary nodules: clinical and imaging features compared with malignancy. Eur Radiol 2019;29:1684-1692.
Sagdeo P, Gattimallanahali Y, Kakade G, Canchi B. Rheumatoid lung nodule. BMJ Case Rep 2015;2015:bcr2015213083.
Koslow M, Young JR, Yi ES, Baqir M, Decker PA, Johnson GB, Ryu JH. Rheumatoid pulmonary nodules: clinical and imaging features compared with malignancy. Eur Radiol 2019;29:1684-1692.
Contributors
Matthew J. Cecchini, MD, PhD
Associate Professor
London Health Sciences Centre
London, Ontario
Canada
Associate Professor
London Health Sciences Centre
London, Ontario
Canada
