Chest ImagingE2396. Pulmonary Lymphoma: A Review of Cross-Sectional Imaging Findings
Lynch P, Landis M. Western Radiology, London, Canada
Address correspondence to P. Lynch (Peter.email@example.com)
Background Information: The pulmonary lymphoid system is the source of a wide variety of lymphoid lesions in the chest. Many of these lesions are benign, but primary pulmonary lymphoma (PPL) is an important diagnostic consideration given it is one of the few malignant lymphoid lesions, and one for which effective treatment is available. A wide variety of appearances can be seen on cross-sectional imaging of the chest, which is often where suspicion of pulmonary lymphoma is first raised given the nonspecific clinical findings.
Educational Goals/Teaching Points: Our aim is to review the anatomy and physiology of the normal and abnormal pulmonary lymphoid system, and demonstrate the wide spectrum of cross-sectional imaging findings seen in PPL.
Key Anatomic/Physiologic Issues and Imaging Findings/Techniques: Within the lungs, the pulmonary lymphoid tissue is comprised of bronchus-associated lymphoid tissue (BALT) and draining lymphatic vessels. BALT tissue consists of clusters of B and T cells found deep to the bronchial epithelium, and it is here where PPL initially develops. PPL is an umbrella term encompassing both Hodgkin Lymphoma and many types of Non-Hodgkin lymphoma originating in the lung. The most common, and thus clinically significant PPL, is the mucosa-associated lymphoid tissue lymphoma, or MALT lymphoma. Classification of a particular subtype is not possible radiologically, as significant overlap exists in the cross-sectional imaging findings of these lymphomas. Airspace consolidation with or without air bronchograms, discrete masses, nodules, and patchy areas of ground-glass attenuation are all characteristics that may identify PPL on CT.
Conclusion: Given the diverse appearances of PPL, an understanding of the imaging features is important to ensure consideration of this malignant diagnosis when appropriate. Knowledge of the pathophysiology involved can help the radiologist understand and appreciate which lesions may be of concern and warrant further investigation.