WCLC 2025 - Posters & ePosters-EP.14.30 Clinicopathological Features and Diagnostic Challenges of Pulmonary Lymphoma: A Retrospective Review of 21 Cases

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This retrospective study reviewed 21 cases of pulmonary lymphoma diagnosed between 2019 and 2025 at a single institution, focusing on clinicopathological features, diagnostic challenges, radiologic findings, and clinical outcomes. Primary pulmonary lymphoma (PPL) is a rare malignancy representing less than 1% of all lymphomas and 0.5% of primary lung cancers. Most PPL cases are mucosa-associated lymphoid tissue (MALT) lymphomas (60–80%), which are indolent, while non-MALT subtypes such as diffuse large B-cell lymphoma (DLBCL), Hodgkin lymphoma (HL), follicular lymphoma (FL), and others are less common and more aggressive.<br /><br />Misdiagnosis is frequent, with 68% of patients initially thought to have pneumonia, lung cancer, or tuberculosis, leading to a median diagnostic delay of six months. Diagnostic approaches vary: MALT lymphomas required surgical excision biopsies for definitive diagnosis as small biopsies were insufficient, whereas high-grade non-MALT lymphomas were often recognizable on small biopsies due to pronounced atypia. Relapsed or systemic lymphomas involving the lung were diagnosed with biopsy supported by clinical history.<br /><br />Radiologically, pulmonary lymphoma presentations are diverse. Common patterns include nodules or masses (30–50%), organizing pneumonia-like patterns (20–40%), and less frequently, sarcoidosis-like or adenocarcinoma in situ-like patterns. Many cases were misdiagnosed radiologically as infections or carcinoma due to overlapping imaging features.<br /><br />Clinically, MALT lymphomas exhibited excellent outcomes, with 90% complete remission and no disease-related deaths during an average 34-month follow-up. Non-MALT subtypes showed a more aggressive course with poorer survival. Early and accurate diagnosis, integrating clinical, radiologic, and pathologic data, is critical to improve prognosis, especially given the differing outcomes between indolent MALT and aggressive non-MALT PPL.<br /><br />In conclusion, recognizing pulmonary lymphoma is challenging but essential. When clinical and imaging findings are incongruent or treatment response is lacking, timely surgical biopsy and multidisciplinary evaluation are vital for accurate diagnosis and management.

Asset Subtitle

Tae-Jung Kim

Meta Tag

Speaker Tae-Jung Kim

Topic Mesothelioma, Thymoma, and Other Thoracic Tumors

Keywords

pulmonary lymphoma

primary pulmonary lymphoma

MALT lymphoma

non-MALT lymphoma

diagnostic challenges

radiologic findings

clinicopathological features

misdiagnosis

surgical excision biopsy

clinical outcomes