Diffuse pulmonary lymphangiomatosis involving lungs and mediastinal soft tissue.

Diffuse pulmonary lymphangiomatosis (DPL) is rare in adults. It is characterized by abnormal proliferation, dilatation, and thickening of the lymphatic channels in the lungs, pleura, and mediastinal soft tissue. Here, we report a case of DPL in a young adult man with recurrent productive cough. Chest computed tomography (CT) showed bilateral interlobular septal and peribronchovascular thickening and mediastinal soft tissue infiltration. Lung biopsy through video-assisted thoracic surgery demonstrated proliferation and dilatation of irregular lymphatic spaces, lined by flattened endothelial cells that were positive for CD31, D2-40, and factor VIII-related antigen on immunohistochemical staining. After treatment with propranolol for six months, the chest CT showed improved interlobular septal and peribronchovascular thickening and a unilateral pleural effusion, which turned bloody. Radiologic features can suggest the diagnosis of DPL. Surgical biopsy with adequate section size is critical in the diagnosis. Propranolol might be an effective and safe therapeutic option for patients with DPL.