Diffuse lung cysts in lymphoid interstitial pneumonia: high-resolution CT and pathologic findings

Lymphoid interstitial pneumonia is part of a spectrum of pulmonary lymphoproliferative disorders that range from benign, small, and airway-centered cellular infiltrates (follicular bronchiolitis, nodular lymphoid hyperplasia) to low-grade malignant lymphoma. Most of the cases occur in patients with underlying autoimmune disease or immunodeficiency. The characteristic high-resolution computed tomography findings consist of diffuse ground-glass opacities, ill-defined centrilobular nodules, bronchovascular thickening, interlobular septal thickening, and scattered thin-walled cysts. The cysts may be seen in up to 80% of the patients and are typically few in number and measure less than 3 cm in diameter. This case illustrates extensive cysts as the predominant high-resolution computed tomography finding of idiopathic lymphoid interstitial pneumonia in a 64-year-old man who underwent unilateral lung transplant. Such extensive cystic disease and lung transplantation treatment has not been previously described.