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268 J VET DENT Vol. 27 No. 4 Winter 2010
Surgery for Cervical, Sublingual, and Pharyngeal Mucocele
STEP-BY-STEP
Mark M. Smith, VMD 
 Mucocele is the most common clinically recognized disease of the salivary glands in 
dogs. A mucocele is an accumulation of saliva in the subcutaneous tissue and the consequent 
tissue reaction to saliva. The mucocele has a nonepithelial, nonsecretory lining consisting 
primarily of fibroblasts and capillaries. The incidence of salivary mucocele reportedly is 
fewer than twenty in 4,000 dogs. Although the condition has been reported in dogs as young as 6-months of age, salivary 
mucocele occurs most often in dogs between 2 and 4-years of age. Salivary mucocele occurs more frequently in German 
shepherds and miniature poodles.1
 Trauma has been proposed as the cause of salivary mucocele because of the activity of young dogs and the documented 
damage to the salivary gland/duct complex and the formation of mucocele. The inability to induce salivary mucocele 
traumatically in healthy dogs suggests the possibility of a developmental predisposition in affected dogs.
 The sublingual gland is the most common salivary gland associated with salivary mucocele. Sialography has shown 
that the origin of the mucocele most often occurs in the rostral portion (that portion of the sublingual gland superimposed on 
the mandible) of the sublingual gland/duct complex. Regardless of the location of origin, mucocele usually forms near the 
intermandibular area (cervical mucocele). Other locations associated with the formation of mucocele because of a sublingual 
gland/duct defect include under the tongue, which involves the floor of the mouth (sublingual mucocele), and the pharynx 
(pharyngeal mucocele).
 The clinical signs associated with salivary mucocele depend on the location of the mucocele. A cervical mucocele is 
initially an acute, painful swelling resulting from an inflammatory response. Cessation of the inflammatory response results in 
a marked decrease in swelling. A decreased inflammatory response allows for the more common presenting history of a slowly 
enlarging or intermittently large, fluid-filled, nonpainful swelling. Blood-tinged saliva secondary to trauma caused by eating, 
poor prehension of food, or reluctance to eat are clinical signs that can be associated with sublingual mucocele. The most 
common clinical signs associated with mucocele of the pharyngeal wall are respiratory distress and difficulty in swallowing 
secondary to partial obstruction of the pharynx.
 Diagnosis of salivary mucocele is based on clinical signs, history, and results of paracentesis. Mucocele paracentesis 
reveals a stringy, sometimes blood-tinged fluid with low cell numbers. Mucin and amylase analyses of the fluid are not 
reliable diagnostic procedures. A chronic cervical mucocele may contain palpable firm nodules that are remnants of sloughed 
inflammatory tissue previously lining the mucocele. Sialoliths are concretions of calcium phosphate or calcium carbonate and 
may occur with chronic mucocele.
 Physical examination and history usually denote the origin of the mucocele. Cervical mucoceles that appear on the 
midline usually shift to the originating side when the patient is placed in exact dorsal recumbency. Sialography can be used to 
determine the affected side if careful observation and palpation are unsuccessful. The most common indication for sialography 
is to determine the location of a salivary gland/duct defect in patients with salivary mucocele. Sialography is also a diagnostic 
aid when considering traumatic injury to one of the salivary glands, salivary neoplasia, a mass or fistulous tract of unknown 
origin in the head and neck region, or a foreign body in the head or neck. The disadvantages of sialography include the need 
for general anesthesia and the difficulty associated with locating the duct opening(s).
 Various methods have been used to treat cervical mucoceles. Mucocele drainage, removal of the mucocele only, and 
chemical cauterization of the mucocele have been reported. The basis for these therapies was the belief that a mucocele was a 
true cyst with a secretory lining. The fact that a mucocele is not a cyst but is a reactive encapsulating structure has prompted 
surgical removal of the affected gland/duct complex. The intimate anatomic association of the sublingual and mandibular 
glands and their ducts requires resection of both structures. Another technique for treating pharyngeal and sublingual 
mucoceles involves marsupialization. However, resective surgery is preferred for pharyngeal mucocele since life-threatening 
upper airway compromise and morbidity from swallowing dysfunction (e.g. aspiration pneumonia) are potential complications 
of conservative management or recurrence. Surgical removal of both the sublingual and mandibular salivary glands, combined 
with drainage of the mucocele, has been advocated for treating cervical, sublingual, and pharyngeal mucocele and is described 
step-by-step.2,3 
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TODO TEXTO UTILIZADO (MENOS IMAGENS)
J VET DENT Vol. 27 No. 4 Winter 2010 269
Figure 1 
Photograph showing a cervical mucocele in a miniature poodle 
dog (A). Salivary mucocele most commonly occurs in the cervical 
region of the dog. The etiology is unknown but the lesion is 
secondary to a defect in the sublingual salivary gland duct 
complex. The resulting mucocele is an accumulation of saliva 
within a non-cystic lining composed primarily of fibroblasts and 
capillaries (B).
Figure 2 
The same defect in the sublingual salivary gland duct complex 
can also lead to pharyngeal (black arrow) [A] and sublingual 
(white arrow) [B] mucocele. Therefore, resection of the mandibular 
and sublingual salivary gland duct complex(s) is recommended. 
The mandibular salivary gland duct complex, although normal, 
requires resection because of its close anatomic association 
with the sublingual salivary gland duct complex. 
Figure 3 
The diagnosis is usually made 
based on cytologic evaluation 
of mucocele fluid obtained by 
paracentesis. Sialography may 
be used to confirm the diagnosis 
or the side of mucocele origin for 
cervical mucocele (A and B). 
A A
B
A B
B
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 270 J VET DENT Vol. 27 No. 4 Winter 2010
Figure 4 
Photographs showing the 
effect of patient position-
ing on determining cervi-
cal mucocele side of origin 
in a large breed dog. With 
the dog in lateral recum-
bency (A), it is difficult to 
determine the predomi-
nant side occupied by 
the mucocele. However, 
with the dog in exact dor-
sal recumbency (B), the 
mucocele seems to be 
predominantly on the right 
side. 
Figure 5 
The side of origin may be difficult to determine especially in small 
dogs with large cervical mucoceles. The clinician may consider 
bilateral resective surgery of the mandibular and sublingual salivary 
gland duct complex(s) as an alternative to the time and frustration 
that is often associated with sialography.
Figure 6 
Surgical landmarks for resection of the mandibular and sublingual 
salivary gland duct complex(s) include the caudal mandible (black 
arrow), vertical ear canal (white arrow), mandibular salivary gland 
(M), wing of the atlas (A), and the larynx (L).
Figure 7 
Surgery for resection of the mandibular and sublingual salivary gland duct complex(s) begins with a skin incision from the caudal aspect of the 
mandible to the origin of the jugular vein (A). The clinical case (B) shows a left-sided mucocele (white arrow) ventral to the mandibular salivary 
gland (*). Note the prominent maxillary and lingual/linguofacial vein tributaries to the jugular vein (black arrow). 
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Figure 8 
Intraoperative photograph (A) in a patient with a cervical mucocele 
showing the result of dissection through the subcutaneoustissues, and platysma and parotidoauricularis muscles to reveal 
the mandibular salivary gland (*) between the maxillary (white 
arrow) and lingual (black arrow) veins. A similar view in the 
cadaver specimen (B) shows the separated vascular structures 
bordering the mandibular salivary gland (*) leading to the jugular 
vein (arrow).
Figure 9 
The mandibular salivary gland (*) is dissected and isolated 
beginning at the caudal aspect (A). Surgical landmarks at this 
point of the surgery (B) include the prominent maxillary (black 
arrow) and lingual/linguofacial vein (grey arrow) tributaries to the 
jugular vein, mandibular lymph node(s) [*], and the digastricus 
muscle (D). 
Figure 10 
Intraoperative (A) and cadaver (B) photographs showing continued dissection and mobilization of the mandibular salivary gland exposing the 
vascular supply to the gland from the medial aspect (arrow). 
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Figure 11 
Dissection continues towards the digastricus muscle (d) 
along the lateral (A) and medial (B and C) monostomatic 
portion of the sublingual salivary gland (arrow) which is closely 
associated with the mandibular salivary gland (*). Dissection 
continues along the polystomatic portion of the sublingual 
salivary gland (arrowheads) until the defect in the gland/duct 
complex is encountered (as pointed to by scissors) [D]. 
Figure 12 
Isolation of the gland/duct defect (arrow) along the 
polystomatic portion (arrowheads) of the sublingual salivary 
gland confirms the correct side for the surgery. Removal 
of the mandibular and sublingual salivary gland duct 
complex(s) without observing a defect obligates the surgeon 
to perform the procedure on the contralateral side.
Figure 13 
Dissection continues through the origin of the sublingual 
salivary gland/duct defect (A), revealing the lining (arrow) of 
the mucocele (B).
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Figure 14 
Fluid contents of the mucocele will leak into the surgical field requiring suction and gauze sponges for removal (A). The color of 
the accumulated saliva will vary from normal to dark motor oil in appearance based on duration of the mucocele and hemorrhage 
contamination from aspiration. The mucocele should be drained by application of a passive drainage system (latex Penrose drain) 
through small incisions independent of the primary incision, and maintained for 3 to 5-days until drainage is minimal. Attempts should 
not be made to dissect and remove the mucocele since it extends through various local tissue planes with the configuration analogy 
similar to tent caterpillar nests (B).
Figure 15 
The sublingual salivary gland/duct defect rarely occurs rostral 
to the lingual nerve (arrow) as it courses over the polystomatic 
portion of the sublingual salivary gland (A). Therefore, the 
sublingual salivary gland/duct is transected and ligated in the 
area (arrow) of the lingual nerve (B). 
Author Information
From the Center for Veterinary Dentistry and Oral Surgery, 9041 
Gaither Road, Gaithersburg, MD, 20878. Email: info@cvdos.com
References
1. Spangler WL, Culbertson MR: Salivary gland disease in dogs and cats: 245 cases (1985-1988). 
 J Am Vet Med Assoc 1991, 198:465.
2. Smith MM. Surgery of the canine salivary system. Comp of Contin Educ Pract Vet 1985; 
 7:457-465.
3. Taney K, Smith MM. Oral and salivary gland disorders. In: Ettinger SE, Feldman EC, eds. 
 Textbook of veterinary internal medicine, 7th ed. Philadelphia: WB Saunders Co, 2010; 
 1479-1486.
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