Bombay Hospital Journal Case R eports[Contents][Home][Archives][Search][Books][Feedback]



*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 showing
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 seen.

Fig.3 Fig.4
Fig.3 CT scan showing a large hypodense non enhancing mass between the genioglossus and mylohyoid muscles. 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.[3] 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 life.[4-7]

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.[3]

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.[13]

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. [14]


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.


1.Oatis GW, Hartman GL, Robertson GR, Sugge WE. Dermoid Cyst of the Floor of the Mouth. Oral Surg 1975; 39 : 192-96.

2.New GB, Erich JB. Dermoid Cysts of the Head and Neck. Surg Gynaec and Obstet 1936; 65 : 48-55.

3.Meyer I. Dermoid Cysts of the floor of the Mouth. Oral Surg 1955; 8 : 1149.

4.Colp R. Dermoid Cysts of the floor of the Mouth. Surg Gynaec and Obst 1925; 40 : 183-95.

5.Ewing J. Neoplastic Diseases, ed. 4, Philadelphia, WB Saunders Company. 1940.

6.Boyd WM. A Textbook of Pathology, ed. 4, Philadelphia, Lea and Febiger. 1944; 308.

7.Orban B. Oral Histology and Embryology, ed. 2, St. Louis. The CV Mosby Company. 1949.

8.New GB. Congenital Cysts of the Tongue, the floor of the mouth, the pharynx and the larynx. Arch Otolaryngol 1947; 45 : 145.

9.Quinn JH, Robinson WC. Multiple Congenital Cysts of the Mouth in a New-born Infant. Oral Surg 1965; 20 : 1.

10.Kinnman J, Suh KW. Dermoid Cysts of the floor of the Mouth. Report of Three Cases. Oral Surg 1968; 26 : 190.

11.Erich JB. Sebaceous, Mucous, Dermoid and Epidermoid Cysts. Am J Surg 1940; 50 : 672.

12.Willis RA. Pathology of Tumours, London, Butterworth and Co., Ltd. 1948.

13.Tuffin JR, Theaker E. True Lateral Dermoid Cyst of the Neck. Int Jour Oral Maxillofac Surg 1991; 20 : 275-76.

14.Leveque H, Saraceno CA, Tang CK, Blanchard CI. Dermoid Cysts of the floor of the mouth and lateral neck. Laryngoscope 1979; 89 : 296-305.

To section TOC
Sponsor-Dr. Reddy's Lab