VEGFD and lymphangioleiomyomatosis: In our study, 25 (32.1%) patients presented with pneumothorax as their first symptom, and 17 (21.8%) developed a pneumothorax during follow-up, similar to the proportions reported elsewhere (15, 19, 20).VEGF-D serves as a current marker for LAM diagnosis and treatment response, and it has been found that patients with lower levels of VEGF-D have a higher frequency of pneumothorax (5).