Question

What is a carotid body tumour (CBT)?

Hint:

The majority of CBTs are benign, but because of their location, they can present challenges in diagnosis and management. Early identification is crucial to avoid complications.

Answer 1

A carotid body tumour (CBT), also known as a chemodectoma, is a rare, typically benign, vascular tumour that originates from the carotid body. The carotid body is a small cluster of chemoreceptor cells located at the bifurcation of the common carotid artery. Its primary role is to monitor blood oxygen levels and help regulate respiratory rate. CBTs occur in about 1-2% of head and neck tumours and are generally asymptomatic until they reach a significant size.
Step 1: Pathophysiology:
CBTs develop due to hyperplasia of the chemoreceptor cells, leading to tumour formation. These tumours are highly vascular, and as they grow, they can compress adjacent structures such as the cranial nerves (IX, X, and XII), the jugular vein, and the carotid artery.
Step 2: Symptoms:
Most CBTs are asymptomatic, but they may present with a painless neck mass, hoarseness (due to recurrent laryngeal nerve involvement), difficulty swallowing (due to glossopharyngeal or vagus nerve compression), or a pulsatile mass due to its proximity to the carotid artery. In rare cases, they can cause a bruit in the neck.