Pathology

1. Chemodectoma
   • Tumour of paraganglion cells of the carotid body located at the bifurcation of the common carotid artery
   • Usually benign (locally invasive)
   • Occasionally malignant with potential to metastasise to local lymph nodes

Approach

• As for neck examination

1. Inspect
   • Located in the anterior traiangle of the neck at the angle of the jaw
   • (Be gentle when examining this area as pressure on carotid bifurcation can induce a vasovagal attack)
2. Palpate
   • Solid and firm
   • Pulsatile but not expansile - may be due to transmitted pulsation from adjacent carotid arteries, overlying palpable external carotid artery, true expansile pulsation from soft or very vascular tumour
   • May be bilateral
   • Due to intimate relationship with carotid artery, can be moved from side to side but not up and down

Investigations for diagnosis

1. Doppler USS
2. Angiography - gold standard - shows hypervascular mass displacing the bifurcation of the carotid artieries
3. CT / MRI to delineate extent of tumour

Treatment

1. Surgical
   • Excision (with preoperative embolisation if the tumour is large)
   • Ultrasonic surgical dissection may also be used
2. Radiotherapy
   • For patients unfit for surgery
   • Large tumours