[A case of diffuse cystic lung disease with severe pulmonary hypertension in a reproductive-aged female].

Pulmonary Langerhans cell histiocytosis (PLCH) and lymphangioleiomyomatosis (LAM) are both rare diseases with low incidence. They not only present characteristic diffuse cystic lesions on chest CT, but also share highly similar clinical manifestations, and most often occuring in young people, which makes differential diagnosis challenging. Here, we reported a case of a reproductive-aged female patient who was initially diagnosed with LAM based on the presence of multiple cystic lesions in both lungs shown by imaging. However, insufficient attention was given to her smoking history and to the specific characteristics and distribution of the cystic lesions. Asher disease progressed, the patient experienced worsening lung function, eventually developing respiratory failure and right heart failure, and bilateral lung transplantation. Taking into account her risk factors, the characteristics of her imaging evolution and pulmonary vascular lesion manifestations, PLCH was considered clinically, and this was confirmed by postoperative pathology.