Liebow and Carrington's original classification of IIP

Transcription

1 Liebow and Carrington's original classification of IIP Eric J. Stern MD University of Washington UIP Usual interstitial pneumonia DIP Desquamative interstitial pneumonia BIP Bronchiolitis obliterans with interstitial pneumonia GIP LIP Giant cell interstitial pneumonia Lymphoid interstitial pneumonia Controversies developed over histological patterns/clinical dx (CFA/IPF) Overlapping terminology Along came HRCT Increasing prognostic importance of separating UIP/IPF from others New ATS/ERS consensus classification system for IIP published (AJRCCM 2002) Devised with input from clinicians, pathologists and radiologists More uniform and consistent set of definitions and criteria Framework for future study 1) UIP NSIP 2) NSIP 3) OP DAD 4) DAD 5) RB DIP 6) DIP 7) LIP usual interstitial pneumonia non-specific interstitial pneumonia organizing pneumonia diffuse alveolar damage respiratory bronchiolitis desquamative interstitial pneumonia lymphocytic interstitial pneumonia each with a clinicopathological counterpart Travis WD, King TE, Bateman F et al. Consensus classification of idiopathic interstitial pneumonias. Am. J. Respir. Crit. Care Med. 2002; 165;

2 1) IPF 2) NSIP 3) COP 4) AIP 5) RBILD 6) DIP 7) LIP Travis WD, King TE, Bateman F et al. Consensus classification of idiopathic interstitial pneumonias. Am. J. Respir. Crit. Care Med. 2002; 165; GIP has been removed now regarded as a pneumoconiosis associated with hard metal exposure Newly recognized/additions non-specific interstitial pneumonia (NSIP) respiratory bronchiolitis-associated interstitial lung disease (RB-ILD) acute interstitial pneumonia (AIP) Old Hamman-Rich Syndrome Provide greater consistency in Dx Identify more pure cohorts for study Emphasize Gold standard for Dx is NOT surgical lung biopsy in isolation Patient better served by clinical, imaging, and histological consensus for final clinical-pathological Dx By far most common of IPs Not all UIP is IPF Not synonyms ACRONYM ALERT I in IPF is Not Interstitial I = IDIOPATHIC pulmonary fibrosis Also seen with several different specific etiologies Drug toxicity Collagen vascular diseases Asbestosis Chronic hypersensitivity pneumonitis Often idiopathic

3 When idiopathic, corresponds with clinical Dx of IPF years old Not an inflammatory disease per se But a defect in wound healing Mean survival from onset of Sx: 4 years Important to separate UIP from other IPs IIP other than IPF Contraction of tissue leads to: Cystic spaces (honeycombing) Traction bronchiolectasis Traction bronchiectasis Typically subpleural and basilar Fibrosis is disfiguring Architectural distortion Reticulation and honeycombing with basilar distribution PPV of 96% for Dx of UIP

4 Can represent inflammation Fibrosis more likely Beware low lung volumes/breathing Spectrum of Alveolar Macrophage Pneumonias in response to cigarette smoke Corresponding spectrum of clinical severity Asymptomatic to profound dyspnea Path depends on extensiveness and location of alveolar macrophage accumulation Separate for now as legacy terms Common incidental finding in smokers (asymptomatic) Macrophages within the resp bronchioles and adjacent alveoli Mild inflam and fibrosis

5 Typically no radiographic/hrct findings May have subtle, ill-defined, centrilobular nodules, upper lobes Seen in areas with centrilobular emphysema Clinical manifestation of ILD associated with pathologic lesion of RB Frequently associated with centrilobular emphysema Whereas RB is common incidental finding, RB ILD more extensive dz, occurs in small %age of smokers,symptomatic yo chronic cough, dyspnea Rarely normal radiographic findings HRCT shows a bit of everything Centrilobular nodules and emphysema Bronchial wall thickening Ground glass (all upper lung predominant) Interstitial fibrosis (mild, lower lobes) Not a specific entity, but a pathologic pattern Uncommon 90+% smokers, yo Rarely, DIP-like appearance seen focally with some drug rxns, dust inhalation, occasionally with UIP Histology: neither desquamative nor predominantly interstitial Alveolar Macrophage Pneumonia Bilateral GGO (filling of alveolar spaces with macrophages) Subpleural and basilar predominance Reticulation common but limited in extent Honeycombing uncommon, limited in extent Assoc emphysema

6 Some overlap in histology RB-ILD bronchiolocentric DIP diffuse Likely represent a spectrum of the same process of alveolar macrophage pneum Smoking-Related Interstitial Lung Diseases FOR NOW, they are distinct entities Originally: Unclassified Interstitial Pneumonia UIP Unfortunate, confusing acronym Unclassified because it doesn t t fit other IP s No temporal heterogeneity like UIP Alveolar macrophages infrequent Organizing pneumonia infrequent No hyaline membranes Lymphocytic infiltrate insufficient No recognized and distinctive clinical counterpart Term is provisional in new classification Often Dx uncertainty still exists NSIP pattern on biopsy should prompt clinician to redouble efforts to find causative exposures

7 Variety of etiologies Some are hypersensitivity pneumonitis with misdiagnosis Idiopathic Drugs Rxn Collagen vascular Dz Resolution of organizing infectious pneumonia HIV Sampling error NSIP and UIP can be seen in same pt/lobe Histologically mixed inflammation and fibrosis Without specific features to allow confident Dx of UIP, DIP, or AIP Cellular type (steroid responsive?) Fibrotic (pts do poorly look/act look/act like UIP) Mixed types Not wastebasket term Holding Pattern Dx Dx of NSIP is BEGINNING of workup, not the end HRCT findings quite variable Patchy/confluent peripheral GGO Irregular linear opacities +/- mild honeycombing Mimics DIP, AIP, UIP, BOOP Non-specific response to various forms of lung injury Pathological hallmark of the distinct clinical entity termed cryptogenic organizing pneumonia Eur Radiol 2002 Jun;12(6): Organizing pneumonia: the many morphological faces.oikonomou A, Hansell DM

8 Clinical suspicion of infection, but no agent is identified Prognosis following steroid treatment is very good Recurrence not infrequent Synonymous with older term BOOP COP preferred: lessens the chance of confusion with constrictive obliterative bronchiolitis (a SAD) Although predominantly intra-alveolar, alveolar, COP can supposedly mimic IPF (therefore in classification) It s s pneumonia! Looks like pneumonia! focal organizing pneumonia variety of nodular patterns bronchocentric distribution Especially in immunocompromised band-like opacities progressive fibrotic form Eur Radiol 2002 Jun;12(6): Organizing pneumonia: the many morphological faces.oikonomou A, Hansell DM focal organizing pneumonia variety of nodular patterns bronchocentric distribution Especially in immunocompromised band-like opacities progressive fibrotic form Ground-glass opacity (90%) Consolidation (90%) subpleural or peribronchovascular middle or lower lung zone Reversed CT halo sign ~20% (AJR aka bird s s nest or Atoll sign Reasonable specificity Also seen eg. Pulmonary Paracoccidioidomycosis AJR 2003; 180: ) Eur Radiol 2002 Jun;12(6): Organizing pneumonia: the many morphological faces.oikonomou A, Hansell DM

9 Comprise a number of clinical pathologic entities which are sufficiently different from one another to be designated as separate disease entities Many areas of uncertainty remain NSIP requires further definition and term should be considered as provisional Correct Dx is a dynamic process Lung biopsy pathologic pattern should be distinguished from clinico-radiologic radiologic- pathologic diagnosis HRCT indicated for all but a small proportion of patients Primary role of HRCT is to separate patients with UIP from those with less specific findings associated with other IIP Describes an idiopathic clinicopathological condition Path: Diffuse Alveolar Damage Clinically: interstitial lung disease causing rapid onset of respiratory failure Synonymous with Hamman-Rich syndrome Radiologically and physiologically: acute respiratory distress syndrome (ARDS) Just idiopathic Represents small subset of patients with idiopathic ARDS Can be confused with other clinical entities Eg. acute exacerbations of pneumonia acute fulminant exacerbation of IPF Grave prognosis with >70% mortality in 3 months, despite mechanical ventilation

10 GGO, consolidation, traction bronchiectasis Vary as disease evolves and fibrosis develops Muller AIP IIPs comprise a number of clinical pathologic entities sufficiently different from one another to be designated as separate entities Many areas of uncertainty remain NSIP in particular requires further definition and should be considered provisional Correct Dx can be dynamic process Histologic pattern should be distinguished from clinico-radiologic radiologic- pathologic diagnosis HRCT indicated for all but a small proportion of patients Primary role of HRCT is to separate patients with UIP from those with less specific findings associated with other IIP