Table of Contents
Definition / general | Anatomy | Epidemiology | Sites | Pathophysiology | Diagrams / tables | Clinical features | Grading | Staging / staging classifications | Prognostic factors | Case reports | Treatment | Clinical images | Gross description | Microscopic (histologic) description | Microscopic (histologic) images | Positive stains | Negative stains | Differential diagnosis | Additional referencesCite this page: Jain A. Squamous cell carcinoma - oropharynx. PathologyOutlines.com website. https://www.pathologyoutlines.com/topic/oralcavitysccoropharynx.html. Accessed May 30th, 2020.
Definition / general
- < 1% of all newly diagnosed cancers and 10 - 12% of cancers in head and neck
Anatomy
- Palatine arch (superior oropharynx): soft palate, uvula, anterior tonsillar pillars and retromolar trigone
- Oropharynx boundaries:
- Anterior: posterior 1/3 of tongue, vallecula, lingual epiglottis
- Lateral: palatine tonsils or tonsillar fossa, posterior tonsillar pillars, glossotonsillar sulcus
- Posterior: posterior and lateral oropharyngeal walls from soft palate to hyoid bone, including pharyngoepiglottic fold
Epidemiology
- Age: sixth - seventh decade (tobacco and alcohol associated cases) vs. fourth - fifth decade (HPV associated cases, although even pre-HPV, rare cases did occur, Otolaryngol Head Neck Surg 1999;120:828)
- Gender: male > female (tobacco and alcohol) vs. male = female (HPV)
- Behavior: tobacco and alcohol consumption, HPV 16, marijuana
Sites
- Most common site is base of tongue
- Tends to extend to lymph nodes in levels II, III and IV of neck
- Higher susceptibility for retropharyngeal nodal disease with lesions along posterior pharyngeal wall or palatine tonsil
- Locoregional spread is typically ipsilateral to the primary site of malignancy; bilateral neck disease can also occur with cancers on the tongue base, soft palate and posterior pharyngeal wall
Pathophysiology
- HPV may exert its carcinogenic effect by integrating its genome into a host cell nucleus by expressing E6 and E7 oncoproteins and inactivating the tumor suppressing p53 and retinoblastoma proteins
Diagrams / tables
Images hosted on other servers:
Head and neck anatomy
Clinical features
- Pain or sore throat, dysphagia and odynophagia
- Referred otalgia, voice changes, hemoptysis
- May present only with a neck mass
Grading
- Grade 1: Well differentiated
- Grade 2: Moderately differentiated
- Grade 3: Poorly differentiated
- Grade X: Cannot be assessed
Staging / staging classifications
TNM staging:
- American Joint Committee on Cancer has designated staging by TNM classification to define oropharyngeal cancer
- See NIH: AJCC Staging Groupings and TNM Definitions [Accessed 25 April 2018]
Prognostic factors
- Carcinomas from palatine arch are less aggressive than those from oropharynx
- Over the last 3 decades, there has been an increase in poorly differentiated tumors and better 5 year survival, attributable to emergence of HPV related oropharyngeal SCC (Laryngoscope 2010;120:2203)
- HPV+ tumors tend to respond well to treatment (Oral Oncol 2010;46:705) but advanced primary lesions are associated with recurrence and death (Laryngoscope 2009;119:1542)
- Occult cervical lymph node metastasis is seen in up to 35% of clinically negative necks (Arch Otolaryngol Head Neck Surg 2003;129:729)
Case reports
- 52 year old man with metastases to lower extremity (Ear Nose Throat J 2013;92:E38)
- 68 year old man with pulmonary lymphangitic carcinomatosis (Oral Oncol 2000;36:125)
Treatment
- Single modality treatment is acceptable for small primary lesions (T1 or T2) or for low neck disease (N0 or N1); combined treatment, such as chemoradiotherapy or surgery with adjuvant radiotherapy, is warranted for higher tumor burdens
- Radiotherapy with surgery as salvage yields 5 year locoregional control of 60 - 76% and 5 year overall survival of 43 - 52% (Int J Radiat Oncol Biol Phys 1996;34:289, Cancer 2002;94:2967)
- Studies are needed to evaluate the impact that HPV vaccinations exert on oropharyngeal SCC
Clinical images
Images hosted on other servers:
Involving soft palate and tonsillar fossa
Gross description
- May be exophytic (verrucous or papillary), endophytic, ulcerated
Microscopic (histologic) description
- Usually moderate to poorly differentiated
- HPV associated cancers tend to be poorly differentiated SCC in a basaloid background
Microscopic (histologic) images
Images hosted on other servers:
Fig 3-9: H&E, p16
Positive stains
Differential diagnosis
- Basal cell carcinoma: commonly involves upper lip, biopsy is diagnostic
