Carotid body tumours are growths that arise in the neck alongside the carotid artery and jugular vein. They are also known as chemodectomas, and are rare but well recognised. The normal carotid body is a tiny structure made of a bundle of cells which monitor oxygen concentration, carbon dioxide content and acidity of the blood travelling to the brain. It is situated on the wall of the main carotid artery as it divides into the two smaller arteries which carry blood to the brain, skull and face. The carotid body has a very rich blood supply.
Carotid body tumours develop from these cells. The tumour gradually expands and tends to splay wide the two main branches of the carotid artery. As it gets bigger, the patient becomes aware of a lump in the neck. This is usually painless but can cause discomfort, voice hoarseness and damage to the surrounding nerves.
About 5 to 10% of tumours affect both sides unless the individual affected comes from a family with a history of carotid body tumours in which case the likelihood of both sides being involved goes up to 30%. Around one in ten carotid body tumours are malignant, that is they contain cancerous cells.
A combination of duplex (doppler-ultrasound) scanning, CT scanning and MRI scanning may all be used to establish a diagnosis of a carotid body tumour.
These tests are helpful in distinguishing a carotid body tumour from other lumps that can arise in the neck. The main condition which may mimic a carotid body tumour is a related condition called a paraganglioma which is a tumour arising from one of the nerves running alongside the blood vessels in the neck. These are easier to remove than carotid body tumours since they are less stuck to the carotid arteries and have a lower blood supply. Other possible causes are lymph nodes, neurofibromas and branchial cysts.
Carotid body tumours slowly but inevitably enlarge if left untreated and may eventually block major blood vessels in the neck. The bigger they grow, the more likely they are to turn malignant, and the more difficult becomes the operation. For this reason it is advisable to remove carotid body tumours even when relatively small. The exception to this is tiny growths detected in a family with a history of the condition. These lumps may be impalpable and only detected on ultrasound, and they can safely be left and monitored with regular scans until they reach an operable size
Carotid body tumours are best treated by surgical removal. This requires a general anaesthetic. The carotid arteries are exposed then the tumour gently separated from the surrounding structures until it can safely be removed.
Carotid body tumours have a very rich blood supply, and are usually stuck to the major blood vessels in the neck as well as surrounding nerves. On occasions, if the carotid artery has been invaded by the tumour, it is necessary to reconstruct the carotid artery to preserve the blood flow to the brain. For these reasons it is essential that the operation be performed by an experienced carotid surgeon who is familiar with operating on the carotid arteries.