RT Journal Article SR Electronic T1 Forced vital capacity decreases rapidly in patients with idiopathic upper lobe-dominant pulmonary fibrosis JF European Respiratory Journal JO Eur Respir J FD European Respiratory Society SP p3750 VO 38 IS Suppl 55 A1 Kentaro Watanabe A1 Taishi Harada A1 Takako Hirota A1 Kazuki Nabeshima A1 Masaki Fujita A1 Nobuhiko Nagata YR 2011 UL http://erj.ersjournals.com/content/38/Suppl_55/p3750.abstract AB We present five patients with upper lobe-dominant pulmonary fibrosis of unknown etiology that does not fit any of the currently defined subsets of idiopathic interstitial pneumonias. We describe the clinical, functional, and pathological characteristics of this disorder, which we have provisionally termed idiopathic upper lobe-dominant pulmonary fibrosis (iULPF).All patients were slender, with a body mass index of 16.0–17.9 kg/m2. Four of the five patients had recurrent pneumothorax. Their pathological characteristics were as follows: 1) upper lobe-dominant subpleural proliferation of elastic fibers associated with deposition of mature collagen in alveolar lumens; 2) isolated fibrotic areas containing alveolar lumens filled with mature collagen were occasionally found in the lung parenchyma distant from the subpleural fibroelastosis; 3) visceral pleura adjacent to the subpleural fibroelastosis were often thickened and contained hyalinized collagen fibers; 4) there was an abrupt transition from subpleural fibrotic areas to less-involved pulmonary parenchyma; and 5) destruction of the lung architecture was minimal and fibroblastic foci were rarely seen. Ventilatory impairment was also characteristic of this condition. The median yearly decline in forced vital capacity in iULPF patients was –20.3% (range, –7.7% to –27.1%), which was more rapid than that reported for chronic fibrosing interstitial pneumonias such as idiopathic pulmonary fibrosis.iULPF is a unique pulmonary fibrosis that results in rapid deterioration of ventilatory function. It should be differentiated from other idiopathic fibrosing interstitial pneumonias.