Cystic lung disease
LAM
LIP
LCH (late stage)
Light chain deposition disease (very rare)
Cystic metastases (e.g. sarcoma)
Pneumatocele from prior infection (pneumocystis, S.aureus, coccidioidomycosis; should resolve over time and not be so numerous as true cystic lung disease)
Birt-Hogg-Dube (very rare)
Centrilobular ground glass nodules
HP RB Follicular bronchiolitis Pulmonary capillary hemangiomatosis (cause of PAH) Plexiform arteriopathy (must have PAH)
Localized multifocal tree-in-bud nodularity
Infectious bronchiolitis (endobronchial spread of infection)
Aspiration
Endobronchial spread of malignancy
Mucous impaction/inflammatory secretions in underlying congenital airway disorders: CF, PCD
Diffuse centrilobular tree-in-bud nodularity
Infectious panbronchiolitis (endobronchial spread of infection) - airway Inhalational panbronchiolitis (toxic/chemical) - airway Foreign body granulomatosis - vascular
Acute pure ground glass opacity
Chronic pure ground glass opacity
Crazy paving - acute
(Similar to acute GGO DDx except:
Crazy paving - chronic
Mosaic attenuation
If hyperattenuating areas are abnormal - GGO DDx If hypoattenuating areas are abnormal (vessels in abN lucent areas are too few in number or small in caliber) - “Mosaic perfusion” 1. Airway causes (abnormal ventilation -> reflex vasoconstriction) *Small airway* • Bronchiolitis obliterans • Asthma • COPD • HP • Chronic bronchitis/small airway infection/mucus plugging *Large airway* • CF • Bronchiectasis 2. Small vessel (vascular obstruction) -Chronic PE -Pulmonary arterial hypertension -Vasculitis
Multiple large nodules/opacities
Multifocal mass-like air space opacities
Multiple peribronchovascular opacities/consolidation
Reverse halo sign/atoll sign
Organizing pneumonia (classic) Vasculitis: Wegener/GPA Pulmonary infarction Fungal (S.American paracoccidioidomycosis, Zygomycosis/mucormycosis) COVID
Halo sign
Invasive fungus (aspergillosis-classic; mucormycosis) Septic emboli Hemorrhagic metastases Viral: CMV, HSV Vasculitis: Wegener/GPA
Organizing pneumonia (rare) Eosinophilic pneumonia (rare)
Perilymphatic nodules
3 locations: subpleural, peribronchovascular, septal
Lymphangitic carcinomatosis
Lymphoma
Sarcoidosis
Silicosis & coal worker pneumoconiosis
Kaposi sarcoma (rare) Lymphoid interstitial pneumonitis (rare) Amyloidosis (rare)
Miliary pulmonary nodules (on CXR)
Disseminated mycobacterial/fungal infection
Hematogenous metastases – papillary thyroid, pancreas, renal cell, melanoma
Pneumoconiosis – silicosis/CWP
Sarcoidosis
Miliary PJP
Bronchiectasis
Postinfectious - Bacterial: Pseudomonas, staph, pertussis - Mycobacterial: TB, MAC - Viral - Mycoplasma Immunodeficiency - Congenital: SCID, hypogammaglobulinemia - Acquired: HIV Mucociliary clearance abnormality - Cystic fibrosis (abnormal mucus) - Primary ciliary dyskinesia (abnormal cilia) - Young syndrome Bronchial obstruction - Bronchial atresia - Endobronchial tumour - Foreign body - Chronic aspiration Bronchial wall abnormality - Mounier-Kuhn (1st-4th order) - Williams-Campbell (4th-6th order) Immune reactions - ABPA - Asthma - Lung transplant rejection - Graft vs. host disease Systemic disease - Alpha 1 antitrypsin deficiency - Collagen vascular disease - IBD
Organizing pneumonia/constrictive bronchiolitis causes
Post infectious: viral, bacterial, mycoplasma, PJP
Post toxic/inhalational injury: smoke, NO2
Connective tissue disorder: Sjogren, rheumatoid arthritis, SLE, scleroderma
Post transplant: lung, heart, heart-lung, bone marrow
Drug reaction: amiodarone, bleomycin, cyclophosphamide, methotrexate, nitrofurantoin
Idiopathic (i.e. COP)
Reticulonodular opacities on CXR
Bronchiectasis/bronchial wall thickening
Emphysema/smoking-related changes with superimposed acute airspace disease
Langerhans cell histiocytosis
Peripheral airspace disease / reverse batwing
Organizing pneumonia
Chronic eosinophilic pneumonia
Sequela of extensive pulmonary thromboembolic disease / pulmonary infarcts
(Infection: COVID)
(Vasculitis)
(Multifocal adenocarcinoma)
Focal interlobular septal thickening
Lymphangitic carcinomatosis
Lymphoma
Kaposi sarcoma
Sarcoidosis
Mediastinal adenopathy
Lymphoma Metastasis Infection – mycobacterial/fungal Sarcoidosis (Castleman, etc.)
Irregular opacity diffuse lung disease – “Dog’s breakfast DDx”
Diffuse malignancy - Multifocal primary - Disseminated pulmonary lymphoma - Not metastasis Atypical disseminated infection Organizing pneumonia
Cavitary lesion
Cavitary neoplasm – metastasis, primary bronchogenic cancer, invasive adenocarcinoma, lymphoma
Infection – mycobacterial/fungal, septic emboli, nocardia/actinomyces
Vasculitis – Wegener
Rheumatoid arthritis
Tracheobronchopapillomatosis (peribronchovascular)
Langerhans cell histiocytosis
If solitary cavitary lesion, add: congenital (sequestration, CPAM, bronchogenic cyst)