EPIDERMOID CYST OF THE FLOOROF THE MOUTH
MAKARAND V DAMLE*, DINAZ K IRANI**, NAVIN L HIRANANDANI***
*Senior Registrar; **Lecturer; ***Hon. Professor and Surgeon, Department
of ENT and Head and Neck Surgery, TN Medical College and BYL Nair Ch. Hospital.
Epidermoid cysts can occur anywhere in the body. In the region of the head and
neck they are more in the midline between the suprasternal notch and the submental
region. They very rarely occur in the floor of the mouth; only 1.6% of 1500
cases studied by New and Erich (1936). This case is presented because of, its
unusual location, its large size causing obstructive signs like dysphagia, dyspnoea
on exertion and dysarthria, and the difficulty encountered in removing the mass.
An epidermoid cyst develops from a misplaced foetal inclusion that takes on
activity and forms a cyst. It commences shortly after birth, but on account
of their slow and painless growth, they attract little attention until their
size gives annoyance. It does not contain any adnexal structures and is lined
by squamous epithelium and may contain cheesy keratinous material. These cysts
present as solid or cystic masses in the midline of the neck between the suprasternal
notch and the submental region. They can also occur lateral to the submandibular
gland. However rarely they may also occur in the floor of the mouth. Painless
swelling is the only symptom, but if the cyst is large, minor obstructive symptoms
can occur. Treatment involves complete excision of the cyst.
A 28 year-old female patient presented
to us with a right-sided neck swelling (Fig. 1) and an intra oral swelling which
was initially small and increased in size over a duration of 8 months. The patient
also complained of dysphagia, dysarthria and dyspnoea on exertion.
|Fig 1 : Properative appearance
a large right sided submandibular mass.
On examination of the neck there was a well circumscribed swelling in the right
submandibular region, extending across the midline to involve the left submental
region. On examination of the oral cavity, there was a swelling in the right
side of the floor of mouth, pushing the tongue to the left side (Fig. 2). Upon
bimanual palpation a dough like, non-tender mass could be felt. The skin and
mucosa over the swelling were intact and normal. On indirect laryngoscopy a
bulge was seen on the right lateral pharyngeal wall and the entire larynx was
pushed to the left. Movement of the head to the right was slightly limited.
| Fig.2 Intraoral photograph
showing a large
mass displacing the tongue to the left
The X-ray neck AP view showed tracheal deviation to the left with mild compression.
A contrast enhanced CT Scan showed a large, hypodense, non-enhancing mass arising
within the sublingual space, between the genioglossus and the mylohyoid muscle
(Fig. 3). The mass extended into the floor of the mouth and the opposite side
in the submental region. Posteriorly it extended to the submandibular space,
compressing the submandibular gland and pushing it posteriorly. The fat planes
around the mass were maintained. Mild shift of or and hypo pharyngeal airway
to the left was seen (Fig. 4). The Fine Needle Aspiration Cytology showed features
characteristic of an epidermoid cyst i.e. presence of epithelial remnants, desquamated
tissue and cellular debris. No tissue of mesodermal or endodermal origin was
| Fig.3 CT scan showing
a large hypodense non enhancing mass between the genioglossus and mylohyoid
||Fig.4 CT scan showing
the largest longitudinal and
transverse diameters of the cyst and shifts of the
oro and hypo pharyngeal airway to the left.
The patient was taken up for surgery. A written informed consent for an elective
tracheostomy was taken, in case intubation was difficult. Under general anaesthesia
with nasal intubation, a transverse incision was made in the right submandibular
area extending beyond the midline to the opposite side. This was carried through
skin, subcutaneous tissue and platysma. The mass was found deep to the superficial
lobe of the right submandibular gland and coursed deep to the mylohyoid muscle
(which was cut). The right submandibular gland was displaced posteriorly. Blunt
dissection was utilized to free the mass, which was removed intact after which
the right submandibular gland was reposited within its capsular bed. The wound
was sutured in layers and a corrugated rubber drain was placed in position.
The specimen consisted of an oval mass of tissue measuring 9 x 5 x 3 cms, the
surface of which was smooth with small collection of shaggy fibrous tissue present
at various points of dissection. It was yellowish white in colour, soft in consistency
and cystic in nature. The mass weighed 270 gms, and upon sectioning, was filled
with a cheesy material. On histopathological examination, features characteristic
of an epidermoid cyst of the floor of the mouth with no evidence of malignancy.
The patient had an uneventful recovery. On follow-up of the patient there is
no evidence of recurrence of the cyst.
Roser, in 1859, first described
dermoid cysts in the floor of the mouth as epidermoid tumours.[1,2]
In a series of about 1500 cases of dermoid cysts, occurred in the floor of the
mouth. In the Head and Neck they arise principally about the eyes, nose in the
floor of the mouth and along the mid-ventral and mid-dorsal lines of closure.
Dermoid should be retained as a clinical term for all types of dysontogenetic
or developmental cysts of the floor of the mouth. A majority
of dermoids are developmental cysts derived from epithelial debris or rests
enclaved during the midline closure of the bilateral mandibular (first) and
hyoid (second) branchial arches. Some of these cysts may be formed by remnants
of the tuberculum impar of His which, together with the lateral processes from
the inner surface of each mandibular arch, form the body of the tongue and floor
of the mouth. These developments take place during the 3rd/4th week of embryonic
The incidence of dermoid cysts in the head and neck region is equal in males
and female.[3,8] Although these cysts usually become manifest
during the 2nd and 3rd decades of life, they have also been seen in new born
infants and infants of few months after birth.[9,10] Clinically
dermoids of the floor of the mouth are frequently quite striking in their appearance.
Those presenting themselves intra-orally, or sublingually may actually displace
the tongue upward to the palate until difficulty in eating, speaking and even
breathing may occur. Those presenting extra orally or submentally usually appear
as pendulous masses beneath the mandible. The cysts generally have a "dough
like" feel, but may feel cystic depending on consistency of the contents,
which may vary from a cheesy, sebaceous substance to a more liquefied material.
These lesions vary in weight from 1 gram to several 100 grams and may vary in
size from a small pea-size growth to one the size of a large grapefruit. Sinus
tracts may develop from these cysts to open either intraorally into the floor
of the mouth or extraorally into the skin beneath the chin. Dermoids may undergo
malignant degeneration and may metastasize to lymphnodes.[2,6,11,12]
The differential diagnosis of dermoid of the floor of the mouth include 1) Ranula
2) unilateral or bilateral blockage of Wharton’s ducts 3) Thyroglossal duct
cyst 4) Cystic hygroma 5) Branchial cleft cysts 6) Acute infection or cellulitis
of the floor of the mouth 7) Infections of submaxillary and sublingual glands
8) Benign and malignant tumors of the floor of the mouth and adjacent salivary
glands. The clinical diagnosis is inconclusive.
Aspirations and Imaging are investigations of value. Sialography gives information
on adjacent salivary glands and infers rather than delineates the cysts. Sonography
is also a useful tool in diagnosing neck masses. Computed tomography reliably
differentiates cystic from solid masses and gives a detailed extent of the mass
in relation to other important structures and helps in the surgical approach,
especially for large cysts.
Treatment is by surgical excision. Surgical excision of the dermoid cysts of
the floor of the mouth is indicated to relieve symptoms caused by the cysts
and prevent their possible infection. An intraoral incision may be used for
small cysts, but large ones require an external approach which avoids intraoral
contamination and allows better visualization and control of surrounding structures.
Elective tracheostomy is indicated in cases of large cysts located deep within
the tongue and the floor of the mouth. This prevents a difficult orotracheal
intubation and post operative upper airway distress from tongue oedema or haematoma.
In dealing with these cysts, presenting laterally in the submaxillary triangle
or medially within the floor of the mouth, it is important to look for and follow
any tract leading to the midline, Mandible or Hyoid bones. This tract may be
lined by epithelium and failure to excise it would invite a recurrence. Post-operative
complications are rare and are reduced by closely following the capsule. Recurrence
is rare but may occur if the cyst is incompletely removed and in difficult cases
post operative supervision with sonographic survey can be helpful. 
Epidermoid cysts in the head and neck region arise principally about the
eyes, nose, in the floor of the mouth and along the midventral and middorsal
lines of closure. Lateral epidermoid cysts occurring in the floor of the mouth
are rare. In this case the interesting features were its rare site i.e. the
floor of the mouth (lateral presentation), its large size causing obstructive
signs like dysphagia, dyspnoea on exertion and dysarthria and the difficulty
encountered during removal of mass.
We would also like to thank the Dean of TNMC Dr. NA Kshirsagar for allowing
us to publish this article.
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