Posterior Hypopharyngeal Wall Squamous Cell Carcinoma


KEY FACTS

Terminology

  • Definition: Squamous cell carcinoma (SCCa) arising from mucosa of posterior wall of hypopharynx (HP) from hyoid bone to esophageal inlet

    • 15% are hypopharyngeal SCCa

Imaging

  • General imaging features

    • Superficial spread superiorly to oropharynx or inferiorly to esophagus

    • Early invasion posteriorly into prevertebral muscles through prevertebral fascia

  • CECT: Irregular, enhancing mass distending lower HP

    • Superior spread to oropharynx (T2)

    • Inferior spread to esophagus (T3)

    • Infiltrate prevertebral muscles (T4b)

      • Imaging not accurate for predicting invasion

      • Preservation of retropharyngeal fat excludes this

    • Carotid encasement or mediastinal invasion (T4b)

  • PET/CT: SCCa is reliably FDG avid

Top Differential Diagnoses

  • Postcricoid region SCCa

  • Cervical esophageal carcinoma

Pathology

  • Strong association with tobacco and alcohol abuse

  • Poor prognosis; overall 5-year survival ~ 30%

Clinical Issues

  • Clinical presentation: Posterior HP wall mucosal lesion

    • Asymptomatic until late, stages III-IV

    • 75% have nodes at diagnosis; often bilateral

    • Up to 50% present with neck mass from nodes

  • Treatment options

    • T1-T2 SCCa: Surgical resection ± radiation therapy (XRT)

    • T3-T4a: Laryngopharyngectomy ± XRT

      • Alternative treatment: Organ preservation chemoXRT

    • T4b: Palliative chemoXRT

Lateral graphic illustrates posterior hypopharyngeal wall SCCa
. These tumors often spread superiorly to the oropharynx or caudally to the esophagus. Invasion of the prevertebral muscles
translates to T4b primary stage.

Axial CECT at the level of the cricoarytenoid joints shows abnormal soft tissue
with ill-defined margins posterior to the cricoid. Poor definition of the prevertebral muscles
is highly suspicious for invasion, and a tumor abuts both common carotid arteries
. This is T4bN1 SCCa.

Axial T1WI MR in an immunosuppressed woman with bilateral lung transplants shows a lobulated mass
arising from the posterior pharyngeal wall. Retropharyngeal fat
is not clearly defined; however, MR has limited accuracy in predicting prevertebral invasion.

Sagittal T2WI FS MR in same patient shows superficial spreading nature of posterior hypopharyngeal wall SCCa
extending superiorly to oropharynx
. Patient was asymptomatic; lesion was only found on clinical examination & was stage T2N1.

TERMINOLOGY

Definitions

  • Squamous cell carcinoma (SCCa) arising from posterior wall mucosa of pharynx from hyoid bone to esophageal inlet

    • Subsite of hypopharynx

IMAGING

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