Radiographic Findings

A frontal chest radiograph shows a large, left pleural effusion and a prominent mediastinum with a widened, right paratracheal stripe consistent with lymphadenopathy. The cardiac size is indeterminate because of the pleural effusion, but may be enlarged.

A detailed image of the right upper lobe of the same radiograph shows several large emphysematous spaces (bullae) in the right apex, consistent with the patient's smoking history. The apex is a common location for paraseptal emphysema, which is subpleural in location and involves the distal part of the secondary lobule. Emphysematous spaces greater than 1 cm in diameter are called bullae [1].

Thoracentesis retrieved exudative fluid (protein, 6.4 g/dl; LDH, 1700 units/dl; WBC, 4300/µl with 46% PMNs, 33% lymphocytes, 17% other, and 4% mesothelial cells; glucose, 92 mg/dl). Gram stain and AFB smear were negative. A CT scan showed a loculated, left pleural effusion, a small right pleural effusion, and a moderate pericardial effusion along with significant mediastinal lymphadenopathy. The parenchyma appeared normal.

Differential diagnosis: There are multiple causes of pleural effusion. The combination of lymphadenopathy with pleural effusion narrows the list somewhat and favors neoplastic or infectious etiologies, although sarcoidosis, Wegener's granulomatosis, systemic lupus erythematosus, asbestosis, and amyloid (with pleural effusion due to heart failure) are considerations [1]. Infections associated with mediastinal adenopathy visible by chest radiography most commonly include tuberculosis and fungal diseases. Bronchogenic carcinoma, metastatic carcinoma, lymphoma, leukemia, and Castleman's disease can also cause pleural effusion and lymphadenopathy [2,3].

References

1. Webb WR, Müller NL, Naidich DP. High-resolution CT of the Lung, 2nd ed. Philadelphia, Lippincott-Raven Publishers, 1996, p 238.

2. Wilson AG. Pleura and pleural disorders. In: P Armstrong, A Wilson, P Dee, D Hansell (eds): Imaging of Diseases of the Chest, 2nd ed. St. Louis, Mosby-Year Book, 1996.

3. Armstrong P. Mediastinal and hilar disorders. In: P Armstrong, A Wilson, P Dee, D Hansell (eds): Imaging of Diseases of the Chest, 2nd ed. St.Louis, Mosby-Year Book, 1996.

Clinical summary Image 1