Primary Pulmonary Lymphoid Lesions: Radiologic and Pathologic Findings

Area of Science:

• Pulmonary Medicine
• Immunology
• Radiology

Background:

• The lung's lymphoid system comprises pulmonary lymphatics and bronchus-associated lymphoid tissue (BALT).
• Key immune cells include dendritic cells, macrophages, and plasma cells.
• Knowledge of normal lung lymphoid anatomy and immunology is crucial for interpreting lesions.

Purpose of the Study:

• To review pulmonary lymphoid anatomy.
• To discuss common primary pulmonary lymphoid disorders, including benign and malignant types.
• To highlight the role of imaging in diagnosis.

Main Methods:

• Review of pulmonary lymphoid anatomy and immunology.
• Classification and description of primary pulmonary lymphoid lesions.
• Emphasis on multidetector chest computed tomography for evaluation.

Main Results:

• Primary pulmonary lymphoid lesions originate from BALT and are uncommon but increasingly recognized.
• Lesions range from benign (e.g., lymphoid hyperplasia, follicular bronchiolitis) to malignant (e.g., MALT lymphoma, non-Hodgkin lymphoma, Hodgkin lymphoma).
• Miscellaneous lesions include lymphomatoid granulomatosis and posttransplant lymphoproliferative disorders.

Conclusions:

• Primary pulmonary lymphoid lesions are diverse and require correlation of imaging, clinical, and pathological findings.
• Multidetector chest CT is essential for evaluating these lesions.
• Increased recognition in immunosuppressed populations necessitates awareness of these conditions.