Benign Tumours of the Lung
Rare but important — distinguishing benign tumours from malignancy and knowing when to resect.
Overview
Benign lung tumours are rare and often discovered incidentally on routine chest imaging. They are classified by cell of origin — developmental/unknown, epithelial, and mesodermal. The most important clinical task is distinguishing them from malignancy.
Classification
| Category | Tumour | Key features |
|---|---|---|
| Developmental / unknown origin | ||
| Most common benign tumour | Hamartoma | See below |
| Teratoma | Rare; 50% benign; all germ layers; exclude mediastinal or testicular origin | |
| Clear cell (sugar) tumour | Resembles renal cell carcinoma; abundant glycogen | |
| Epithelial | ||
| Bronchial adenoma | See separate chapter — carcinoid, adenoid cystic, mucoepidermoid | |
| Papilloma | Rare; solitary or multiple; bronchoscopic excision; high recurrence | |
| Mesodermal | ||
| Most common mesodermal | Fibroma | Tracheobronchial origin; collagenous/spindle cells; bronchoscopic resection if pedunculated |
| Second most common | Chondroma | Arise in major bronchi; may show calcification; Carney's triad: pulmonary chondroma + extra-adrenal paraganglioma + gastric GIST |
| Lipoma | Rare; intrabronchial; male predominance; associated bronchiectasis; bronchoscopic removal for small lesions | |
| Leiomyoma | From smooth muscle of bronchioles or pulmonary vessels; 50% intrabronchial; surgical excision | |
| Sclerosing haemangioma | From type II pneumocyte precursors; presents as SPN; may cause haemoptysis; excision | |
Hamartoma — in detail
The most common benign lung tumour, most often discovered as an asymptomatic SPN. Hamartomas contain normal lung elements (fat, epithelium, fibrous tissue, cartilage) in disorganised growth. Peripheral parenchymal hamartomas are slow-growing and asymptomatic. Endobronchial location causes obstructive symptoms.
Imaging: Rounded lesion with smooth margins. CT shows characteristic intranodular fat and popcorn calcification — when both are present, the diagnosis is virtually certain.
Management: Peripheral asymptomatic hamartomas — observe after definitive diagnosis. Central or symptomatic — surgical excision. Malignant transformation is extremely rare.
Despite minimal malignant potential, hamartomas cannot always be distinguished from carcinoid or malignant tumours on imaging alone. When imaging findings are non-diagnostic, VATS wedge excision provides simultaneous diagnosis and treatment and is the preferred approach for peripheral lesions.
All clinical content should be verified against current guidelines before clinical application. This resource is intended for revision and educational purposes only.
Standard textbooks
- Shields TW, LoCicero J, Reed CE, Feins RH. General Thoracic Surgery. 7th ed. Lippincott Williams & Wilkins.
- Sellke FW, del Nido PJ, Swanson SJ. Sabiston & Spencer Surgery of the Chest. 9th ed. Elsevier.
- Pearson FG, et al. Thoracic Surgery. 3rd ed. Churchill Livingstone.