Soft tissues of the oral cavity Flashcards
According to Jones 2020 in Vet Surg, how did the volume of brachycephalic tongues compare to those of mesaticephalic patients?
Volume of the tongue greater relative to body weight and skull length (relative macroglossia).
Also 10 times denser. Proportion of air/soft tissue in the oropharynx and nasopharynx reduced by 60%.
In a study by Goldschmidt 2023 in JAVMA, what percentage of dogs with oral cancer had a major incidental finding on skull and neck CT scan? When head CT, lymph node CT, thoracic screening, and AUS were performed what was the chance of a major finding in at least 1 test? What patients had the highest prevalence of metastatic disease at the time of staging?
5% of dogs had major incidental findings on skull and neck CT scan (predominantly secondary extraoral tumours). Risk of major incidental findings was increased with age.
28% (or 1/4) patients had a major finding on either head CT, lymph node cytology, thoracic screening, and AUS. Major incidental findings were most commonly identified with AUS in 1 of 12 patients (although metastatic disease most commonly identified on thoracic imaging).
Oral malignant melanoma, oral SCC, and T3 tumours had the greatest prevalence of metastatic disease.
In a study by Treggiari 2023 in JVIM, what was the MST for dogs with tonsillar carcinoma? What were 4 factors associated with improved survival?
MST 126 days.
Surgery (MST 196 days), chemotherapy, use of NSAIDs, and absence of clinical signs were associated with improved survival.
Distant metastasis occurred in 15% of patients, majority pulmonary. Of the 76% of dogs that had regional LNs sampled, 80% had regional metastasis.
What nerve supplies motor innervation to the lips and cheek?
Facial nerve
What nerve supplies sensory innervation to the lips and cheek?
Trigeminal nerve
What vessels supply the lips and cheeks?
Branches of the facial supply the lower lips, branches of the infraorbital the upper.
What nerve innervates the extrinsic muscles of the tongue? What are the three main extrinsic muscles of the tongue?
Hypoglossus nerve.
The three main muscles are the genioglossus, styloglossus, and hyoglossus.
What is the name of the mucosal fold that runs longitudinally adjacent to the frenulum of the tongue and ends at the sublingual caruncle?
Sublingual fold
What nerve controls the actions of the intrinsic muscles of the tongue?
Hypoglossal nerve
Label the following diagram.
What are the gustatory and nongustatory papillae of the tongue?
Gustatory: fungiform, vallate, foliate.
Nongustatory: filiform, conical.
What artery is the lingual artery a branch of? Where does the lingual vein empty?
The external carotid. The lingual vein empties into the facial vein.
Which muscles make up the soft palate?
Tensor and levator veli palatini, palatine, palatopharyngeal, pterygopharyngeal.
What nerves control the muscles of the soft palate?
The vagus and glossopharyngeal nerves.
What vessel supplies the soft palate?
Minor palatine artery (a branch of the maxillary artery).
What is the main arterial supply of the palatine tonsil?
The tonsilar artery (a branch of the lingual artery)
Where do the efferent lymphatics of the tonsils drain?
The mandibular and retropharyngeal lymph nodes
What is the name of the additional tonsils seen in cats?
The paraepiglottic tonsils (craniodorsal to the base of the epiglottis).
What are the phases of deglutition?
- Oropharyngeal
a. Oral: formation of a food bolus. Sensory and motor innervation supplied by the facial, trigeminal, and hypoglossal.
b. Pharyngeal: tongue and pharyngeal constrictor muscles transport the food bolus to the pharynx. The epiglottis covers the larynx and the palate the nasopharynx. Under the control of the vagus and glossopharyngeal nerves.
c. Pharyngoesophageal: passage of food through the cricopharyngeal sphincter. Terminates with closure of the sphincter, also under the control of the vagus and glossopharyngeal nerves. - Esophageal
- Gastroesophageal
Which lymph nodes receive afferent lymphatic drainage from the oral cavity?
The parotid, mandibular and medial retropharyngeal. The superficial cervical lymph nodes should also be sampled as they receive afferent lymphatics from the aforementioned nodes.
Nodes on both sides should be sampled as lymph vessels can cross midline.
Why should spring loaded mouth gags be avoided in cats?
Can cause compression of the maxillary arteries and neurologic deficits, including blindness.
What is the most common congenital disorder affecting the lips in dogs?
Primary cleft palate
What are surgical treatment options for tight lip syndrome (only described in Shar-Peis)?
Incision of the lip mucosa at the gingival margin to allow the lip to retract, excising a segment of skin on the chin to pull the lip margin ventrally, deepening of the rostral and lateral vestibule.
What surgery is described for treatment of lower lip redundancy and eversion?
Anti-drool chelioplasty, alternatively the redundant fold of tissue can be resected with a full-thickness wedge resection.
How is traumatic lip avulsion surgically corrected?
Small lesions can be left to heal by second intention.
Large avulsions often occur at the gingival margin which has poor holding power, may require placement of suture subgingivally around incisor teeth or the use of bone tunnels.
What are the most common tumour types of the canine and feline lip?
Canine: melanoma, SCC
Feline: SCC, mast cell tumours, fibrosarcomas.
What is the MST for dogs with lip melanoma?
34 months with excision of well-differentiated tumours. May be less for poorly differentiated disease.
What is the metastatic rate for oral nontonsillar SCC?
0-38%
When might buttons be useful in closure of the lip?
In resections of the commissure, to prevent unzipping of the incision.
What reconstructive technique of the lip is depicted?
What is the most common site of penetrating oral injury?
Directly underneath the tongue
Why is the tongue a rare site for infection?
Rich blood supply, ability to avoid penetrating injury, tough dorsal surface, continual contact with saliva.
What are the three types of calcinosis circumscripta? Is the tongue a common site?
Dystrophic: secondary to trauma.
Metastatic: due to abnormal calcium balance.
Idiopathic: unknown cause.
The tongue is the second most common location. Treatment is not usually required unless dysphagia is present.
What are the most common malignant oral tumours in dogs?
What is the most common site for oral tumours in dogs?
Melanoma, SCC, fibrosarcoma
Gingiva, followed by tonsils and lips.
What are the most common malignant oral tumours in cats?
What is the most common site for oral tumours in cats?
SCC (70-80%), fibrosarcoma.
Gingiva and tongue.
What breeds of dog are at increased risk of lingual melanoma and SCC?
Melanoma: Shar Pei, Chow Chows
SCC: Poodles, labradors, Samoyeds. Female dogs predisposed
Which part of the tongue is most commonly affected in cats with lingual SCC?
Ventral portion near the frenulum.
What are 4 risk factors in cats for developing squamous cell carcinoma?
Canned food diets, canned tuna fish, flea collars (5 x incidence), environment with a smoker.
Compare to study by Zaccone in JVIM that found the following risk factors: rural environment, outdoor access, environmental tobacco smoke, and petfood containing chemical additives.
What percentage of malignant melanoma of the mouth are amelanotic?
33%
Which lymph nodes should be sampled when staging oral melanoma?
Ideally mandibular, retropharyngeal and parotid. Only 54% of dogs with regional lymph node metastasis have mandibular lymph node involvement.
What is the MST for lingual melanoma and SCC in dogs?
Melanoma: 216 days
SCC: 241 days
Survival much longer for both tumours when lesions <2cm (818 days).
Local recurrence reported in 28% of dogs following glossectomy.
What surgical margin is recommended for tumours of the tongue?
2cm. Less than 1cm margins associated with an increased risk of recurrence.
How can large wedge excisions of the tongue be closed?
The rostral portion of the tongue can be rotated up to 90 degrees.
What are the different types of glossectomy?
Partial: amputation of the free portion of the tongue rostral to the frenulum.
Subtotal: removal of the entire free tongue and a portion of the genioglossus and geniohyoid muscles caudal to the frenulum.
Near total: >75% of the entire tongue.
Amputation: total glossectomy.
What percentage resection of the tongue is well tolerated in dogs and cats?
50% in the dog. Glossectomy less well tolerated in cats.
What is the MST for SCC of the oral cavity in cats?
44 - 203 days.
What are the most common causes of dysphagia?
Space occupying mass, congenital abnormalities, functional abnormalities.
What are the most common pharyngoesophageal dysphagias?
Cricopharyngeal asynchrony and cricopharyngeal achalasia.
What are common sites of penetrating injury to the pharynx?
Esophagus, lateral and dorsal pharyngeal walls, sublingual region.
What structure needs to be carefully preserved when performing a ventral midline exploration for penetrating pharyngeal foreign body?
The recurrent laryngeal nerves
What is the most common tonsillar neoplasia in dogs and cats?
SCC
What is the regional and distant metastatic rate for canine tonsillar SCC?
73% regional, 42% distant.
70% of dogs had normal sized lymph nodes on palpation in one study despite 45% of these having metastatic disease.
What is the MST for dogs with tonsillar SCC?
2 months.
In a more recent study the combination of tonsillectomy +/- chemo +/- radiation resulted in prolonged survival (212 days).
Presence of metastatic disease does not seem to affect survival, most likely due to difficulty in controlling the primary tumour.
What is the MST for cats with tonsillar SCC?
2-14 weeks.
