title: Diagnostic Approach to Advanced Fibrotic Interstitial Lung Disease: Bringing Together Clinical, Radiologic, and Histologic Clues.
abstract: BACKGROUND
  - Idiopathic pulmonary fibrosis (IPF) is a distinctive clinicopathologic entity and the most common form of progressive diffuse lung scarring in older adults. Idiopathic pulmonary fibrosis manifests histopathologically as the usual interstitial pneumonia pattern. The usual interstitial pneumonia pattern is distinguished by geographically and temporally heterogeneous fibrosis that is peripherally accentuated, often with honeycombing and traction bronchiectasis. Idiopathic pulmonary fibrosis is not the only disease that leads to end-stage lung fibrosis, however, and several other entities may also cause advanced fibrosis. Surgical lung biopsies often present a diagnostic dilemma when they show clear evidence of advanced fibrosis, but the clinical, imaging, and/or histopathologic subcharacteristics suggest something other than IPF.
  
  
  OBJECTIVE
  - To address this dilemma, we review several other fibrotic lung diseases, including connective tissue disease-associated interstitial lung disease, chronic hypersensitivity pneumonitis, advanced pulmonary Langerhans cell histiocytosis, end-stage pulmonary sarcoidosis, Erdheim-Chester disease, Hermansky-Pudlak syndrome, and others, detailing their clinical, radiologic, and histopathologic attributes and emphasizing similarities to and differences from IPF.
  
  
  METHODS
  - Data sources comprised published peer-reviewed literature and personal experience of the authors.
  
  
  CONCLUSIONS
  - Often, clues in the lung biopsy may offer the first suggestion of a fibrotic lung disease other than IPF, and accurate classification is important for prognosis, treatment, and the development of future therapies.
authors.forename: Brandon T
authors.initials: BT
authors.lastname: Larsen
authors.forename: Maxwell L
authors.initials: ML
authors.lastname: Smith
authors.forename: Brett M
authors.initials: BM
authors.lastname: Elicker
authors.forename: Jessica M
authors.initials: JM
authors.lastname: Fernandez
authors.forename: Guillermo A Arbo-Oze
authors.initials: GAA
authors.lastname: de Morvil
authors.forename: Carlos A C
authors.initials: CAC
authors.lastname: Pereira
authors.affiliation: From the Department of Laboratory Medicine & Pathology (Drs Larsen, Smith, and Leslie), Mayo Clinic, Scottsdale, Arizona; the Department of Radiology (Dr Elicker), University of California, San Francisco; Juan Max Boettner Hospital (Drs Fernandez and Arbo-Oze de Morvil), Asunción, Paraguay; and the Department of Medicine (Dr Pereira), Federal University of São Paulo, São Paulo, Brazil.
authors.forename: Kevin O
authors.initials: KO
authors.lastname: Leslie
mesh_terms: D001706:Biopsy; D006801:Humans; D017563:Lung Diseases, Interstitial / Q000175:diagnosis*