Spatial Distribution Patterns of Pleural Dissemination in Patients With Thymoma and Survival Analysis

Background: Thymoma is a common malignancy with low incidence, and pleural metastases are common pattern of recurrence. It is necessary that the spatial location of pleural metastatic lesions be analyzed. This study aimed to analyze the spatial distribution patterns of pleural dissemination in patients with thymoma and evaluate the variables that influence the survival of pleural metastasis in this population. Methods: This retrospective study investigated hospital admissions of patients diagnosed with pleural metastasis from thymoma. The spatial distribution pattern and visualization of the pleural metastases were analyzed after establishing a coordinate system. We further analyzed the survival and influencing factors in patients with pleural metastases from thymoma. Results: The analysis included 56 patients with a cumulative count of 365 pleural metastases, with 351 metastases from Zones 1-5 finally included in the analysis. The spatial distribution of the 285 initially diagnosed pleural metastases was significantly concentrated in Zones 3 and 4 near the lateral half of the spine (56.5%), followed by Zone 5 (17.5%). Collectively, these two components accounted for 74.0% (211/285) of all initial metastatic lesions. The survival rates at 5 years for those who underwent surgery versus nonsurgical treatment were 68.3% and 37.1%, respectively (p=0.015). Univariate Cox regression analysis showed that surgical intervention reduced the risk of death by 61%. Conclusions: The distribution of pleural metastatic lesions exhibited a nonuniform pattern, primarily concentrated on the spinal aspect below the aortic arch of the costal pleura and the spinal aspect of the diaphragmatic pleura.