The authors of the study on ambulatory oxygen (AO) in oxygen-dependent chronic obstructive pulmonary disease (COPD) acknowledge that their findings, showing no improvement in quality of life or walking distance with AO over 3 months, contradict current guidelines recommending both stationary and mobile oxygen delivery systems. They argue that the negative results are not due to insufficient sample size, as repeated trials in 100 different patient groups would likely show that the treatment effect is below clinically significant thresholds. They also address variations in oxygen saturation during the 6-minute walk test and mean arterial oxygen tension (PaO2), noting that patients with more severe hypoxemia may have more advanced disease and are more likely to be house-bound. While some patients with oxygen-dependent COPD might benefit from AO, the study suggests that acute responses do not predict long-term quality of life improvements. The authors emphasize the importance of identifying such patients through further research. In response to the article on pulmonary lymphangioleiomyoma, the authors recall a case of a 46-year-old male with spontaneous pneumothorax on both sides, which was later diagnosed as pulmonary lymphangioleiomyoma. They highlight the importance of considering this rare condition in patients with bilateral cystic lung lesions and normal pulmonary function tests. The differential diagnoses include lymphangioleiomyoma, tuberous sclerosis, Langerhans cell histiocytosis, and eosinophilic granuloma. The case underscores the need for careful evaluation of such lesions, especially in young patients presenting with spontaneous pneumothorax.The authors of the study on ambulatory oxygen (AO) in oxygen-dependent chronic obstructive pulmonary disease (COPD) acknowledge that their findings, showing no improvement in quality of life or walking distance with AO over 3 months, contradict current guidelines recommending both stationary and mobile oxygen delivery systems. They argue that the negative results are not due to insufficient sample size, as repeated trials in 100 different patient groups would likely show that the treatment effect is below clinically significant thresholds. They also address variations in oxygen saturation during the 6-minute walk test and mean arterial oxygen tension (PaO2), noting that patients with more severe hypoxemia may have more advanced disease and are more likely to be house-bound. While some patients with oxygen-dependent COPD might benefit from AO, the study suggests that acute responses do not predict long-term quality of life improvements. The authors emphasize the importance of identifying such patients through further research. In response to the article on pulmonary lymphangioleiomyoma, the authors recall a case of a 46-year-old male with spontaneous pneumothorax on both sides, which was later diagnosed as pulmonary lymphangioleiomyoma. They highlight the importance of considering this rare condition in patients with bilateral cystic lung lesions and normal pulmonary function tests. The differential diagnoses include lymphangioleiomyoma, tuberous sclerosis, Langerhans cell histiocytosis, and eosinophilic granuloma. The case underscores the need for careful evaluation of such lesions, especially in young patients presenting with spontaneous pneumothorax.