These are a special class of tumours called paragangliomas found in the neck at the junction of the blood vessels feeding your neck and brain. These are rarely occurring in about 1 in 50,000 population with approximately 85% sporadic in origin. Multiple cases can be seen in running in families(10 -15%), people living in high altitude regions and those of African descent.
These are slow-growing in nature and usually become noticeable in the 20 – 50 year age group. Some of these tumours actively secrete chemicals that may cause elevation in blood pressure.
They are typically seen as a painless neck swelling which is slow growing and are sometimes diagnosed while being examined for other illness.
Imaging studies like CT angiogram or MR angiogram are done to see the size of the tumour and its relation to the various structures in the neck. These tumours are known to spread locally and often involve the blood vessels feeding the brain and face completely along with vital nerves and veins. Rarely these tumours are malignant(5%) with distant metastasis. These tumours sometimes release chemicals that can cause increased blood pressure and a test to confirm that may be done if clinically indicated. If catecholamine levels are elevated, an evaluation for adrenal pheochromocytomas should be performed. If detected these tumours should be removed prior to the carotid surgery. FNAC or biopsy is not indicated in the majority of cases as imaging is diagnostic.
Surgical excision is the main modality of treatment and the higher the grade of tumour the more difficult the surgery is with the risk of involvement of other structures.
Such patients are at a high risk of carotid resection due to the tumour’s involvement. There are risks of cranial nerve injuries (IX, X, XI, XII), bleeding, infection, the possibility of a carotid bypass with vein grafts, stroke.
Embolization of carotid body tumours has been a controversial topic. It has been recommended by some centres when the size of the tumour exceeds 4 cm in size. Blood loss appears to be less with prior embolization of larger tumours but has not been found to be true across all studies.
Typically some sore throat and voice change may be seen for 2 to 5 days which gradually recovers over a week. For patients with nerve involvement with higher-grade tumours, nerve excision may produce changes with voice and swallowing which can be recovered with therapy over 6 – 8 weeks.