Lymphocytic interstitial pneumonia - Follow-up CT findings in 14 patients

The aim of the present study was to assess the evolution of various compute d tomographic (CT) findings of lymphocytic interstitial pneumonia (LIP) wit h determination of potentially reversible or irreversible features. The stu dy included 14 patients with biopsy-proved LIP who had serial thin-section CT examination 4 to 82 months (median 13 months) apart. Initial and follow- up CT scans were evaluated independently and then directly compared with ea ch other by two observers. The main parenchymal abnormalities on the initia l CT scan consisted of ground-glass attenuation (n = 14), thickening of int erlobular septa (n = 13), centrilobular nodules (n = 12), cystic airspaces (n = 10), and airspace consolidation (n = 4). On follow-up CT, nine patient s improved, one showed no change, and four showed increased extent of disea se. With the exception of cysts, the parenchymal opacities were reversible. On follow-up CT, new cysts were seen in three patients; these developed ma inly in areas with centrilobular nodules on initial CT. Honeycombing was se en on follow-up CT in four patients; in three patients it developed in area s of airspace consolidation and in one patient it developed in an area with ground-glass attenuation on initial CT. The majority of patients with LIP improved on follow-up. However, airspace consolidation may progress to hone ycombing and centrilobular nodules may precede cystic formation.