Abstract
BACKGROUND: Diffuse pulmonary lymphangiomatosis (DPL) is a rare pulmonary disorder, which affects the lymphatic channels from the mediastinum to the pleura. DPL is often misdiagnosed or missed due to the lack of clear specificity and definitive medical therapies. In most cases, the disease progresses to chronic morbidity or even death. CASE PRESENTATION: Here, we have reported a case of DPL in a 17-year-old boy who presented with hemoptysis and progressive breathlessness. The diagnosis was confirmed based on the typical imaging features observed through high-resolution computed tomography, chest magnetic resonance imaging, and lymphangiography. Furthermore, we have presented the genetic characteristics of the patient and his parents and discovered the following heterozygous variants of BCL6: NM_001706: exon5: c. A463G (p.M155V) and ATM: NM_000051: exon3: c.A107G (p.D36G). The patient underwent treatment with sirolimus for 2 months; his clinical symptoms disappeared completely, and the mediastinum soft mass shrank dramatically. CONCLUSIONS: Early diagnosis of DPL is challenging for clinicians, and imaging plays an important role in determining the location and severity of the disease. The gene mutation detected in this study may facilitate the pathogenesis of DPL. Sirolimus can prevent further disease progression in the short term, which may be an effective and safe therapeutic alternative for treating DPL.