Prominent nodular elastosis in a subset of patients with UIP pattern. Radiological-pathological correlation.

<bold>Background:</bold> Pulmonary nodular elastosis is a localized intraparenchymal process characterized by the accumulation of elastic fibers. In this analysis we aimed to describe this process, when associated with UIP pattern. Materials and methods: patients showing with nodular elastosis as proven by transbronchial criobiopsy associated with a corresponding nodular pattern in the CT scan were prospectively collected in the last two years. CT findings were analyzed and scored by two chest Radiologists. <bold>Results:</bold> Four patients (2 males, 2 females) were included in the analysis; one former smoker and three nonsmokers, with age range of 46-69 year-old, and a common clinical history of dry cough and progressive dyspnoea on exertion. Past medical history was remarkable for early greying of the hair (n=1), evidence of familial history of lung fibrosis (n=1), weight loss (n=1). CT findings were characterized by a nodular pattern in the upper lobes, with a lobular distortion, scattered bone metaplasia nodules. Probable or indeterminate UIP pattern was present in the lower lobes. Histology was characterized by centrilobular fibroelastotic tissue settled in a patchy fashion in the upper lobes samples. In these samples dilated lymphatics inside the elastotic scars , scattered fibroblastic foci and foci of bone metaplasia were present as well. In the samples obtained from the lower lobes a more typical UIP pattern (with a combination of patchy fibrosis, fibroblastic foci +/- honeycombing) was always present. The fibrotic tissue in these samples was constantly rich in elastin. <bold>Conclusions:</bold> Nodular elastosis and UIP define a subset of patients with peculiar CT and clinical presentation.