22Honeycombing: significance a very important finding in practicefibrosis is presentUIP is likely the histologic patternin the absence of a known disease, IPF very likelylung biopsy is uncommonly performed if significant honeycombing is visible
36Traction Bronchiectasis bronchiectasis resulting from fibrosiscorkscrew appearancemucous plugging absentbronchioles may be involvedassociated with other findings of fibrosis (e.g. reticulation or honeycombing).
41Traction Bronchiectasis: significance fibrosis is very likely presentuseful in diagnosis when a reticular abnormality is unassociated with honeycombingUIP and IPF are common causesother causes of fibrosis (i.e. sarcoidosis, HP, NSIP) are more likely than when honeycombing presentbiopsy often indicated unless the patient has a C-V disease
42Nodules - anatomic distribution (Colby) lymphatic distribution - along lymphaticsrandom distribution - random relative to lung structuresbronchiolocentric - centrilobular airwaysangiocentric - in relation to small vessels
43Nodules - anatomic distribution (HRCT) perilymphatic distributionrandom distributioncentrilobular distribution
44Perilymphatic nodules nodules in relation to lymphaticssubpleural nodulesperibronchovascular nodulesseptal nodulespatchy distribution
45Perilymphatic Nodules: differential diagnosis sarcoidosislymphangitic spread of tumorsilicosis and CWP (uncommon)amyloidosis (rare)LIP (rare)
82Centrilobular Nodules: significance small airways disease (e.g. bronchiolitis) most likelyconsider infectionwith appropriate history, may be diagnostic of hypersensitivity pneumonitisremember BACbecause of relation of nodules to airways, transbronchoscopic biopsy often diagnostic in patients with infection or tumor
83Tree in bud: diagnosisdilatation and impaction of centrilobular airwaysresembles a budding treecentered mm from the pleural surfacemore conspicuous than normal branching vesselsoften associated with centrilobular nodules
84“tree-in-bud” dilated, impacted centrilobular bronchioles clustered centrilobular nodules or rosettes.