Squamous cell carcinoma of the hypopharynx is relatively uncommon, carries the worst prognosis of any head and neck squamous cell carcinoma (HNSCC), and is a challenge to diagnose and treat.
Hypopharyngeal carcinoma is relatively uncommon representing only 10% of all proximal aerodigestive tract malignancies. Squamous cell carcinomas account for ~95% of all primary tumours of the hypopharynx.
The epidemiology of hypopharyngeal SCC is essentially the same as that of other HNSCC, and is typically encountered in patients with a long history of smoking tobacco and alcohol consumption 1-2. As such they are more common in males, with perhaps the exception of posterior cricoid tumours which may be more common in women (especially of northern Europe) with Plummer-Vinson syndrome 2,6.
Most frequent presenting symptoms are those of dysphagia or odynophagia. As these tumours often present late, other frequent presenting symptoms include a neck mass (either representing the tumour or nodal metastases; the latter being the presenting symptom in up to a quarter of patients), change in voice quality (due to involvement of the larynx of laryngeal innervation), or even systemic symptoms such as weight loss 2.
Piriform sinus tumours have a tendency to cause referred pain to the external acoustic meatus due to cross innervation with neurons of the internal laryngeal nerve and auricular nerve, both branches of the vagus nerve (CN X) 2,6.
Stenotic tumours near the pharyngo-oesophageal junction may result in severe dysphagia and even near obstruction.
The hypopharyngeal subsite are not evenly involved 2:
- piriform sinus: 66-75%
- posterior pharyngeal wall
- posterior cricoid / pharyngo-oesophageal junction
Human papilloma virus may also play a role, although it is isolated in far fewer patients with hypopharyngeal SCC (16%) compared to oropharyngeal SCC 1-2. See main HNSCC article for a general discussion.
Imaging is essential not only in diagnosing likely SCC but also staging the tumour (see hypopharyngeal SCC staging).
As dysphagia is a common presenting symptom, a barium swallow is often the first examination requested. Small sessile or superficially spreading lesions can be difficult or impossible to diagnose. Larger lesions may be visualised as irregular filling defects or result in asymmetry.
The primary tumour typically appears as a solid soft tissue nodule or region of superficial thickening with increased enhancement. When the tumour extends beyond the confines of the pharynx, the surrounding fat planes are obliterated. It should be noted however that such stranding may be due to an inflammatory response rather than necessarily representing tumour invasion 6.
Careful assessment of cervical lymph nodes is essential as up to 75% of patients with hypopharyngeal SCCs have nodal metastases at the time of diagnosis 6.
Following irradiation CT can be challenging, as irradiated mucosa often becomes oedematous, and soft tissue fibrosis may develop, obliterating or distorting normal fat planes and potentially mimicking tumour involvement 5.
MRI has the ability to be superior to CT in local staging and assessing perineural spread however relatively long acquisition times and degradation by motion artefact are sometimes challenging 3.
- T1: intermediate to low signal mass
- T2: intermediate to high signal
T1 C+ (GAD):
- enhancement usually present
- larger tumours of nodal metastases may be centrally necrotic
FDG PET-CT has an increasing role play in diagnosis, staging and follow-up of head and neck malignancies, allowing identification of metabolically active tumour deposits. As is the case with FDG-PET elsewhere size is a limitation, as is movement artefact and presence of dental amalgam artefact 4.
Treatment and prognosis
Treatment of hypopharyngeal squamous cell carcinoma usually involves surgical resection and/or radiotherapy.
Squamous cell carcinoma of the hypopharynx carries the worst prognosis of any SCC of the upper aerodigestive tract of the head and neck both because it often presents with advanced disease. Even when prognosis is corrected for stage, hypopharyngeal cancers continue to have poor outcomes 1.
- stage I-II: 47% 5-year survival
- stage III-IVb: 30% 5-year survival
- stage IVc: 16% 5-year survival
- non-squamous cell malignancy:
- accessory salivary gland tumours
- radiation change in the setting of irradiation for malignancy elsewhere in the head and neck
- retropharyngeal abscess
- 1. Current Diagnosis and Treatment Surgery Thirteenth Edition. Gerard Doherty. McGraw-Hill Medical ISBN:0071635157 (find it at amazon.com)
- 2. Head and Neck Cancer. Louis B Harrison (Editor), Roy B Sessions (Editor), Waun K Hong (Editor). Lippincott Williams & Wilkins ISBN:0781771366 (find it at amazon.com)
- 3. Kataoka M, Ueda H, Koyama T et-al. Contrast-enhanced volumetric interpolated breath-hold examination compared with spin-echo T1-weighted imaging of head and neck tumors. AJR Am J Roentgenol. 2005;184 (1): 313-9. AJR Am J Roentgenol (full text) [pubmed citation]
- 4. Goerres GW, Von Schulthess GK, Hany TF. Positron emission tomography and PET CT of the head and neck: FDG uptake in normal anatomy, in benign lesions, and in changes resulting from treatment. AJR Am J Roentgenol. 2002;179 (5): 1337-43. AJR Am J Roentgenol (full text) [pubmed citation]
- 5. Hermans R, Pameijer FA, Mancuso AA et-al. Laryngeal or hypopharyngeal squamous cell carcinoma: can follow-up CT after definitive radiation therapy be used to detect local failure earlier than clinical examination alone? Radiology. 2000;214 (3): 683-7. Radiology (full text) [pubmed citation]
- 6. Head and neck imaging. Ed. by Peter M. Som, Hugh D. Curtin. St Louis (Mo.) : Mosby-Year Book, 2003. ISBN:0323009425 (find it at amazon.com)