BENIGN LUNG TUMOURS

Pulmonary hamartoma

This is the most common benign tumour of the lung and is usually seen on the X-ray as a very well-defined round lesion 1-2 cm in diameter in the periphery of the lung. Growth is extremely slow, but the tumour may reach several centimetres in diameter. Rarely it arises from a major bronchus and causes obstruction.

Bronchial carcinoid

This rare tumour resembles intestinal carcinoid tumour and is locally invasive, eventually spreading to mediastinal lymph nodes and finally to distant organs. It is a highly vascular tumour that projects into the lumen of a major bronchus causing recurrent haemoptysis. It grows slowly and eventually blocks the bronchus, leading to lobar collapse. As foregut derivatives, bronchial carcinoids may produce ACTH but do not usually produce the 5-hydroxytryptamine that is seen in midgut or hindgut carcinoid tumours.

Cylindroma, chondroma and lipoma

These are extremely rare tumours that may grow in the bronchus or trachea, causing obstruction.

Tracheal tumours

Benign tumours include squamous papilloma, leiomyoma, haemangiomas and tumours of neurogenic origin.