Lymphocytic interstitial pneumonia characterized by diffuse cystic lung lesions: Single-center, cohort retrospective analysis

<bold>Objective of the Study:</bold> The aim of this study is to investigate the clinical features and differential diagnosis of secondary LIP, and to provide evidence-based medical evidence for the standardized clinical treatment of LIP. <bold>Research Methods:</bold> By retrospectively analyzing the clinical data of 32 patients with secondary LIP and 32 patients with LAM. analysis of the clinical features of the secondary LIP, and the differential diagnosis with LAM. <bold>Results:</bold> The average age of the 32 LIP patients was 44.10 years (range 26-66 years). (1) The degree of LAM lung function impairment is usually greater than that of the LIP cohort. (2) HRCT of LIP shows diffuse ground-glass-like shadows in both lungs. HRCT of LAM showed scattered thin-walled air-containing cystic cavity shadows in both lungs. (3) Biopsy of the lacrimal glands in patients with LIP is characterized by lymphocytic infiltration and spread into the interstitium (>50 lymphocytic foci.) The definitive diagnosis of LAM ultimately relies on histopathologic examination of the lungs. <bold>Conclusion:</bold> LIP is a relatively rare cause of diffuse cystic lung disease. LIP lung imaging is easy to misdiagnose and miss the diagnosis clinically due to its lack of specificity, and it should be differentiated from other rare cystic lung diseases based on the typical clinical features, serologic indexes, and pathologic features.