Download Causes Of Cavitary Lung Lesions

Causes of cavitary lung lesions
Bacterial infections
o Community acquire pneumonia – especially Klebsiella pneumoniae and Staphylococcus
aureus
o Pulmonary actinomycosis
 Very aggressive – chest wall invasion, transfissural extension and hilar and
mediastinal lymphadenopathy may be seen
o Septic emboli
 Cavitary lesion usually in periphery of lung
 Multiple lesions usually found
 “feeding vessel” sign may be present on CT
Primary lung cancers
o Squamous cell ca 82%
o Adenocarcinoma
o Large cell carcinoma
o Small cell carcinoma never cavitates
 Cavitation is reported in 2-16% of primary lung Ca
 Multiple cavitary lesions are rare but suggestive of multifocal bronchoalveolar cell ca
 Measurement of cavity wall thickness is most useful in predicting malignancy
o ≤ 4mm – 94% benign
o 5mm to 15mm – 60% benign and 40% malignant
o >15mm – 90% malignant
 Other features of cavities on CT scan suggestive of malignancy
o Notching – 29% benign 54% malignant
o Irregular internal wall – 26% benign and 49% malignant
 Findings suggestive of benign origin
o Linear margin
o Bronchial wall thickening
o Consolidation and
o Ground glass attenuation
o ‘air-crescent’ sign s/o inflammatory process
Pulmonary metastases
 Occurs less frequently than in primary cancers
 4% of metastatic lung tumors may show cavitations

Squamous cell ca most common – 69%
Non malignant cavitary diseases
 Tuberculosis
o Common in post primary TB
o Usually located in apical and posterior segments of upper lobes and superior segments of
lower lobes
o Prevalence of 30-50% of TB patients
o May be multiple with thick/thin walls
o Very difficult to radiologically differentiate TB and malignancy
 Nontuberculous mycobacterial infection
o Mycobacteria kansasii and M.avium-intracellulare complex
o 65% of MAC patients have cavitation
o Associated findings include nodules with associated Bronchiectasis
 Fungal infections
o Aspergilloma – usually in a pre-existing cavity
 Round soft tissue within pre-existing cavity
o Cryptococcois
 Cavitation in 14-42% of cases, no differentiating features
o Pulmonary blastomycosis
o Histoplasmosis
o Coccidioidomycosis
o Mucormycosis
 Non infectious inflammatory diseases
o Necrobiotic Rheumatoid nodules

Typically men with subcutaneous nodules, high RF and pulmonary interstitial
pneumonia
 Multiple nodules may be seen
o Wegener’s granulomatosis
 May present as single nodule with cavitation or multiple
 Cavitation occurs in 50% of cases
 Lesions represent active disease and may resolve on treatment
o Eosinophilic granulomatosis
 Sparing of costophrenic sulci hallmark of disease
Miscellaneous rare cause of cavitation
o Immunosuppressed patients
 Aspergillosis
 Pulmonary nocardiosis
o Use of novel chemotherapy agents – cavitation of existing lung ca
o Post radiotherapy ablation of tumors