Primary Pulmonary Lymphomas.

Area of Science:

• Oncology
• Pulmonology
• Hematology

Background:

• Primary lung lymphoma (PLL) is rare, accounting for <0.5% of primary lung tumors.
• PLL presents with nonspecific symptoms and can mimic other lung conditions radiologically.
• Histologic confirmation is essential for diagnosing PLL.

Purpose of the Study:

• To review the clinical, radiologic, pathologic, and molecular characteristics of B-cell and T-cell primary lung lymphomas.
• To highlight the diagnostic challenges and differential diagnoses for various PLL subtypes.
• To provide a comprehensive overview of primary lung lymphoma subtypes, excluding Hodgkin lymphoma and posttransplant lymphoproliferative disorder.

Main Methods:

• Review of clinical, radiologic, and pathologic features of primary lung lymphomas.
• Discussion of immunohistochemical markers, flow cytometry, and molecular methods for diagnosis.
• Analysis of differential diagnoses based on lymphoma subtype.

Main Results:

• Primary lung marginal zone lymphoma (MALT type) comprises 70-80% of PLL cases.
• Other B-cell subtypes include diffuse large B-cell lymphoma and lymphomatoid granulomatosis (LyG).
• T-cell PLLs, like anaplastic large cell lymphoma, are rare; LyG is an EBV-driven process causing vasculitis.

Conclusions:

• Accurate diagnosis of PLL subtypes requires a combination of clinical, imaging, and histopathologic evaluation.
• Differential diagnosis varies significantly among PLL subtypes, necessitating specific diagnostic approaches.
• Understanding the diverse characteristics of PLL is crucial for appropriate patient management.