Abstract Introduction Lymphangioleiomyomatosis (LAM) is a rare and slowly progressive cystic lung disease characterized by abnormal proliferation of smooth muscle like cells, affecting multiple organ systems, predominantly in women of reproductive age. Its major manifestations include progressive dyspnea, recurrent pneumothorax and chylothorax. The reported incidence and severity of hemoptysis in LAM range widely. While most cases are mild, some patients experience massive, life-threatening bleeding, particularly during pregnancy. Methods We retrospectively analyzed the demographic, clinical, imaging and functional characteristics of patients with LAM and hemoptysis treated at our center, and systematically reviewed published case reports in PubMed and Embase to summarize clinical features, etiologies, interventions and outcomes. Results We retrieved a total of 46 patients with LAM and hemoptysis, all of whom were female with a 43-year-old median age when diagnosed LAM. At the time of hemoptysis, 10.9% (5/46) were postmenopausal. Hemoptysis was mainly associated with physical exertion (especially swimming) and upper respiratory tract infection. Based on the most severe manifestation recorded, 60.5% (26/43) of patients presented with blood-stained sputum and the other 39.5% (17/43) with hemoptysis. Abnormal lymphatic manifestations were observed in 23.9% (11/43) of patients. Pulmonary function testing performed at baseline or at the most recent assessment following hemoptysis showed that 28 of 42 patients (66.7%) had a percent predicted diffusing capacity of the lung for carbon monoxide(DLCO%p) below 60%. 90.5% (38/42) of patients experienced mild clinical interventions, performing a generally benign course. However, pregnant patients with LAM and hemoptysis tended to be more severe and required more urgent management. In our cohort, three cases were pregnant at the time of hemoptysis episode, among which one patient developed life-threatening massive hemoptysis at her 32 weeks of twin pregnancy. After an emergency cesarean, the patient required extracorporeal membrane oxygenation(ECMO) support, mechanical ventilation and corticosteroid therapy, subsequently achieving gradual recovery. Conclusions Hemoptysis is a rare but important clinical manifestation in LAM patients. The occurrence of hemoptysis appears to be linked to pulmonary vascular and lymphatic dysfunction secondary to LAM cell infiltration, and may be exacerbated by specific physiological states such as pregnancy, reflecting a multifactorial process involving vascular, lymphatic and hormonal factors. Although most cases are mild and resolve with conservative measures, massive hemoptysis, particularly during pregnancy, requires coordinated multidisciplinary management. Recognizing patients with high risks early may help clinicians anticipate and mitigate severe outcomes. This abstract is funded by: Beijing Science and Technology Innovation Foundation for University or College students
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