SQUAMOUS CARCINOMAS OF THE ORAL MUCOSA

SQUAMOUS CARCINOMAS OF THE ORAL MUCOSA  

Plan : 

       Introduction 

       Definition 

       Anatomical and histological reminders of the oral mucosa

       Epidemiology

 Particularities of carcinomas of the oral mucosa:

 The circumstances of discovery

 Clinical forms of squamous cell carcinomas 

              – the ulcerative form

              – the ulcero-vegetative form

              – the vegetative form

        Differential diagnosis  

  Positive diagnosis 

        Topographical forms 

• Tongue cancer 
• Cancer of the floor of the mouth 
• Lip cancer

       Conclusion

2022/2023

Squamous cell carcinomas of the oral mucosa

INTRODUCTION :

Oral cavity cancers are part of upper aerodigestive tract (UADT) cancers. In 90% of cases, they are squamous cell carcinomas of the oral mucosa.

The average age of patients is 60 years. Men are more affected than women.

The prognosis is poor for all oral cavity cancers. 

DEFINITION : 

Oral squamous cell carcinoma is a cancer that develops in the epithelium of the oral mucosa. 

    ANATOMICAL AND HISTOLOGICAL REMINDERS: 

            It is the mucous membrane that covers the inner wall of the lips and the oral cavity; it is continuous with the skin at the vermilion junction, the outer side of the lips.

It continues behind with the digestive (pharynx) and respiratory (larynx) mucosa.

The oral cavity is entirely lined by a mucosa resting on the connective, muscular and bony planes. The mucosa consists of a lining epithelium resting on the lamina propria through a basement membrane. 

SQUAMOUS CARCINOMAS OF THE ORAL MUCOSA

THE EPITHELIUM:

It is paved, multi-stratified, keratinized or not depending on the location. It includes:

• A germinative cell layer (stratum germinatum), backed by the basement membrane. Consisting of cubic cells on one or two layers; these cells are the least differentiated of the epithelium. This layer also contains melanocytes and Langerhans dendritic cells.
• A Malpighian mucous body (stratum spinosum). The cells are larger and begin to flatten (this phenomenon becomes more pronounced as the cells migrate towards the surface.
• A granular layer (stratum granulosum) which is only present in areas of keratinized mucosa; is made up of large, flattened cells containing grains of keratohyalin (sulfur protein which will give keratin). 
• A superficial layer whose cells desquamate (stratum corneum). In this layer, the elongated, disunited cells contain organelles, their nucleus more or less degenerated. 

BASAL MEMBRANE:

Elle constitue l’interface entre épithélium et le chorion. C’est une mince bandelette qui épouse les ondulations des crêtes épithéliales.

La membrane basale joue un rôle important, filtrant les échanges, permettant l’attache des kératinocytes, influant leur différenciation et leur renouvellement et sa rupture est décisive dans l’invasion des cancers.

LE CHORION :

Il est constitué par un tissu conjonctif fibroélastique présentant des aspects variés selon les territoires. Il est lâche, richement vascularisé dans sa partie superficielle ou papillaire. Il renferme des glandes salivaires accessoires mixtes (séromuqueuses) ou muqueuse et des terminaisons nerveuses.

     Epidémiologie : 

Dans le monde, il est répertorié environ 400.000 nouveaux cas de carcinomes épidermoïdes oraux (CEO) par an : ¼ dans les pays développés contre ¾ dans les pays en voie de développement. 

Plus d’un malade sur deux décède de ce cancer dans les 5 ans qui suivent l’établissement du diagnostic. 

Cependant, son incidence varie en fonction du pays, de la distribution inégale des facteurs carcinogènes et peut-être aussi en fonction de la sensibilité individuelle à ces derniers. 

Aux Etats-Unis et au Royaume-Uni, les cancers oraux ne représentent que 2% de la totalité des cancers, alors que dans des pays tels que l’Inde et le Sri-Lanka, cas exceptionnels, ils représentent près de 40% de la totalité des cancers. 

Il est estimé que le carcinome épidermoïde est responsable de 90% des tumeurs de la cavité orale. 

Les patients âgés de plus de 65 ans sont plus touchés.

1. Particularités des carcinomes de la Muqueuse Buccale :

• Ils peuvent siéger sur toutes les muqueuses orales, mais le plus souvent nous les retrouvons au niveau de la langue,  du plancher  et des gencives ;
• Quelque soit la localisation topographique et la forme clinique de ces lésions, la palpation révèle une induration caractéristique qui déborde très souvent la tumeur.

2.  Les circonstances de découverte

• La symptomatologie des cancers de la cavité buccale est souvent fruste au début de l’évolution.
•  Ainsi, les patients consultent souvent tardivement. Ceci souligne tout l’intérêt d’un examen systématique de la cavité buccale chez tout sujet d’âge mur alcoolo-tabagique. 
• Les signes révélateurs sont essentiellement :

• La  découverte d’une lésion  muqueuse ou gingivale (ulcération, bourgeon nodule, fissure);
• Des troubles de la déglutition : dysphagie, une glossodynie souvent associée à une otalgie ;
• Gène à l’élocution témoignant souvent d’un envahissement lingual important ;
• Une ou des adénopathies cervicales dures 
• Des saignements, le plus souvent peu abondants, à type de crachats sanguinolents.

3.   FORMES CLINIQUES DES CARCINOMES EPIDERMOIDES

• Malgré que la cavité buccale soit  facilement accessible à l’examen clinique direct, le diagnostic des carcinomes épidermoïdes de la muqueuse buccale est souvent fait trop tardivement. 
• For 2/3 of patients, the lesion is only diagnosed if it reaches stage T2, or even T3 or T4, and there are already cervico-facial lymph node metastases in half of the cases.
•  This diagnostic delay changes the prognosis. 

Classically, there are three main clinical forms of squamous cell carcinomas in the oral cavity:

– the ulcerative form

–  the ulcero-vegetative form

–  the vegetative form

We also find some rarer atypical forms such as:

– the atypical ulcerative form

– the cracked shape

– the sheet shape (extended on the surface)

– the infiltrating form 

– the interstitial form

Initially, squamous cell carcinoma is not painful and pain appears only late. The mucosa near the tumor may have a normal appearance but, more often, it is erythematous or keratotic.

We will only deal here with the ulcerative form and the vegetative form.

1. The ulcerative form  : this is a common form; it is characterized by:

  –  a more or less irregular, hardened, raised, sometimes everted edge. This edge has two slopes:

•  An external covered by healthy or congested mucosa 
•  And an internal one extends with the bottom of the ulceration.

–  an indurated base , more or less extensive in depth, which always extends well beyond the limits of the ulceration. This lesion most often bleeds easily on contact, especially at an advanced stage. Pain is generally absent.

 2. The vegetative or exophytic form 

It appears as a budding, more or less thick, protruding from the healthy mucosa. 

3. Ulcerative-vegetative form 

This is the most common form. It combines the two aspects previously described.

4. Differential diagnosis:

  Differential diagnosis: is done with  

– Traumatic ulceration 

– Giant canker sores,

– syphilitic or tuberculous ulcers

– Gingivoalveolar carcinoma confused with chronic periodontal disease.    

SQUAMOUS CARCINOMAS OF THE ORAL MUCOSA

Positive diagnosis: based on 

• The clinic 
• X-rays 
• Biological examinations 
• The biopsy 

V. Topographical forms:

1. Tongue cancers:

Often taken as a type of description of oral cavity cancers. These are squamous cell carcinomas in 90% of cases. 

Carcinoma of the mobile portion of the tongue:

• Ulcerative vegetative forms are frequent or pure budding, an interstitial nodule is very rare;

 Cancers of the base of the tongue:

• They are located behind the lingual V. The warning signs are discreet and early diagnosis is exceptional. 
• Late diagnosis: The lesion escapes direct visual examination and the warning signs are discreet and not very suggestive. When they exist: 

• intermittent earache, 
• limitation of lingual protraction;
• deviation of the tongue to the affected side;
• Frequent lymphadenopathy;

2. Cancers of the floor of the mouth:

Anterior buccal floor:

• It is easy to access the exam.
• The carcinomas have an ulcerous appearance, less often vegetative, sometimes fissured.
• In pelvi-gingival forms, often fissured, the extension occurs towards the pelvi-lingual groove and the lower surface of the mobile tongue, but also towards the internal table of the mandible; the progression then crosses the crest and reaches the vestibular mucosa, then the lower lip, more quickly in the edentulous.

Posterior buccal floor:  

• The symptomatology is often dominated by difficulty in protraction of the tongue, difficulties in swallowing;
• Reflex earaches are very common. 
• The appearance of trismus marks the invasion of the medial pterygoid muscle.

 3. Lip cancers: 

Lower lip cancer: 

• Its preferred location is the vermilion of the lower lip. 
• It appears as an ulcerative, ulcero-vegetative or ulcerated and crusted lesion (a common form of lip carcinomas) on a precancerous lesion with a dyskeratotic appearance, often secondary to smoking. 
• -The diagnosis is early. 
• -The prognosis is good and lymph node extension is only observed in the event of late treatment. 

Upper lip cancers:

• They are rare: 5% of lip cancers.
• In this area, we find more lymphomas and interstitial nodular tumors on accessory salivary glands.

4. Cancers of the mucous membrane of the inner side of the cheek:

• The vegetative form is the most common. 
• Traumatic origin (dilapidated tooth or aggressive prosthesis), white precancerous lesion, dysplasia or lichen.
• Due to rapid spread to soft tissues and early cervical lymph node dissemination, cancer of the inner side of the cheek has a poor prognosis.

SQUAMOUS CARCINOMAS OF THE ORAL MUCOSA

5. Cancers of the vestibular sulci:

• Vestibular carcinomas are rare 
• They mainly affect the middle and posterior regions of the lower vestibule ;
• Precancerous lesions are common;
• Adenopathies are generally early, present in 50% of cases at the first examination;
• Extension occurs deep into the soft tissues and into adjacent bone. 

6. Gum cancers:

• frequent;
• most often the ulcerative-budding aspect is confused with a defective periodontal state;
• In gingivomandibular forms, bone invasion may be responsible for anesthesia in the V3 territory.
• an X-ray examination is necessary to look for bone invasion.

7. Carcinoma of the palatine mucosa:

• It is very rare, if we exclude secondary invasion of a neighboring carcinoma (gum, veil).
• It is mainly in this region that tumors of the accessory salivary glands are seen: mucoepidermoid carcinomas and adenoid cystic carcinomas.

Conclusion

The prognosis for upper aerodigestive tract cancers remains very poor.

Currently we will only obtain better results through Prevention , the latter involves:

• Raising awareness among at-risk populations in order to establish regular consultations.
• The establishment of anti-smoking and anti-alcohol campaigns, in the hope of raising awareness among the population;

• A complete and systematic examination of the oral cavity with the aim of detecting, diagnosing and treating precancerous lesions and cancers in their early forms; this task is particularly the responsibility of the dentist, the practitioner who examines the mouth daily.
• Dental crowns are used to restore the shape and function of a damaged tooth.
  Bruxism, or teeth grinding, can cause premature wear and often requires wearing a retainer at night.
  Dental abscesses are painful infections that require prompt treatment to avoid complications. Gum grafting is a surgical procedure that can treat gum recession. Dentists use composite materials for fillings because they match the natural color of the teeth.
  A diet high in sugar increases the risk of developing tooth decay.
  Pediatric dental care is essential to establish good hygiene habits from an early age.
   

SQUAMOUS CARCINOMAS OF THE ORAL MUCOSA