Congenital Intraoral Dermoid and Epidermoid Cyst with Orocutaneous Fistula Presenting with Life-threatening Airway Obstruction in an Infant

ABSTRACT

Dermoid cysts and epidermoid cysts in the floor of the mouth are rare in the pediatric age group. In this case report, we have discussed the presentation, management, and literature review of a 6-month-old female child presenting with both dermoid and epidermoid cysts in the floor of the mouth with an orocutaneous fistula.

INTRODUCTION

Dermoid cysts of the head-and-neck areas are developmental lesions resulting from congenitally displaced or trapped ectoderm during the midline fusion of the first and second branchial arches during the 3^rd and 4^th week of development.[1,2] Dermoid cysts in the floor of the mouth are rare accounting for between 1.6% and 6.5% of all dermoid cysts and comprise only 0.01% of all oral lesions within pediatric populations.[1,2]

Congenital dermoid cyst in the floor of the mouth with associated orocutaneous fistula is extremely rare and has never been reported in the English literature. We present a case of a 6-month-old female child who initially presented to us with an orocutaneous fistula and later presented with life-threatening airway obstruction and diagnosed to have an intraoral dermoid cyst.

CASE REPORT

A 6-month-old female child presented with a history of watery and milk discharge from the undersurface of the chin, aggravated by food intake for the last 3 months. A methylene blue fistulogram test had been performed elsewhere through the submental opening, and dye was seen inside the oral cavity and diagnosed as a congenital orocutaneous fistula. Subsequently, the child presented to a local hospital with inflamed neck swelling and respiratory distress. The child was intubated and initially managed as Ludwig’s angina with intravenous antibiotics and mechanical ventilation and later shifted to our hospital.

On examination, there was a solitary swelling of about 5 cm × 6 cm at the floor of the mouth lifting the tongue superiorly, tense, with elevated temperature and redness of overlying skin with a single discharging sinus below the chin and profuse salivary secretions from the oral cavity. Approximately 20 ml of pus was aspirated from the inflamed swelling. Blood investigations revealed a hemoglobin of 11.7 g/dL, white blood cell count of 17,888 cells/mm³, platelet 371,000/μL, and a positive C-reactive protein level. Pus culture had growth of coagulase-negative staphylococcus sensitive to meropenem and vancomycin. A contrast-enhanced computed tomography scan of the head and neck revealed a well-defined thick-walled cystic lesion (3.7 cm × 5 cm × 4 cm) with incomplete septa in the floor of the mouth with fistulous cutaneous communication (8 mm × 4 mm) in the submental region with the possibility of an infected plunging ranula or infected dermoid or epidermoid cyst, with a few inflammatory fibrotic bands [Figure 1a].

Figure 1.

(a) Sagittal view showing well-defined thick-walled cystic lesion with incomplete septa in the floor of mouth with fistulous cutaneous communication in the submental region, (b-d) Axial diffusion-weighted imaging image, (b) shows a hyperintense lesion (arrow 1) in the anterior aspect of the tongue base, (c) axial apparent diffusion coefficient image with corresponding hypointensity (arrow 2) suggestive of an epidermoid cyst, (d) sagittal T2 fat-suppressed image shows a septated cystic lesion in the tongue with an external cutaneous opening in the submental region

The child was initially managed in the pediatric intensive care unit with mechanical ventilation and with intravenous meropenem and vancomycin. Later, a complete intraoral excision of the cyst was done in the operating theater. Gross pathological evaluation revealed a 1.3 cm × 1.9 cm × 0.3 cm thick-walled cystic mass containing grayish-white material. Microscopically, the cyst wall was lined by the stratified squamous epithelium with intact granular layer and skin appendages [Figure 2a]. The cyst contents were composed of keratin flakes, and there was no evidence of malignancy. The histopathological findings confirmed the diagnosis of a dermoid cyst.

Figure 2.

(a) Cyst lined by the stratified squamous epithelium with intraluminal keratin, surrounding areas shows the presence of adnexal structures (arrow) (H and E, ×50), (b) cyst lined by the stratified squamous epithelium with intraluminal keratin (H and E, ×50)

After 6 months, we repeated magnetic resonance imaging (MRI) of the neck and floor of the mouth which confirmed a residual lesion in the floor of the mouth between the genioglossus muscles extending downward through a fistulous tract into the skin of the submental region [Figure 1b-d]. The residual lesion was completely excised through a submental approach, and the histopathology suggested it to be an epidermal cyst containing keratin flakes [Figure 2b]. The child is doing well in follow-up and thriving well.

DISCUSSION

Orocutaneous fistula is a pathologic communication between the oral cavity and the cutaneous surface of the face. Malignancy, dental infections, salivary gland lesions, branchial fistula, and trauma are the most common causes. Congenital orocutaneous fistula is extremely rare and has been reported to be associated with ectopic salivary glands and submandibular aplasia.[3] Dermoid cysts with associated discharging sinuses in the lip, nose, tongue, orbit, or other midline sites of the head and neck have been previously reported.[4] However, it has never been reported in association with intraoral dermoid cysts.

Floor-of-mouth dermoid cysts are rare in children and usually present in the second or third decade of life due to its slow growth. However, they are of major clinical importance due to their potential impact on deglutition, speech, and respiration. A sudden growth in size due to associated infection causing rapid expansion and extension into the neck obstructing the upper airway is the significant reason for seeking medical emergency. In our case, the methylene blue test conducted elsewhere was the main reason behind the development of infection and created suspicion regarding the disinfection and sterilization techniques followed by them.

Imaging plays a crucial role in the diagnostic workup and surgical planning of floor-of-mouth masses. MRI has been proven to be superior in differentiating epidermoid and dermoid cysts from other etiologies.[5] Dermoid and epidermoid cysts typically show low T1 signal with homogenous hyperintensity on T2, while ranulas are hyperintense on T1 due to their high protein content.[1,5]

Complete surgical excision is the treatment of choice in floor-of-mouth dermoid cysts. The choice of surgical access should depend on the size and location of the cysts. The mylohyoid muscle separates the sublingual space from the submental and submandibular spaces and is the key landmark used to determine whether an intraoral or cervical approach is most appropriate. Lesions above the mylohyoid are typically operated through an intraoral approach, and those below the muscle are removed using a cervical/extraoral approach.[2,5] However, sometimes, it needs both approaches as done in our case. The prognosis following complete surgical removal is excellent, and postoperative complications, recurrence, or malignant transformations are exceedingly rare.[5]

CONCLUSION

Both dermoid and epidermoid cysts in the floor of the mouth with orocutaneous fistula are extremely rare. A radiological investigation, preferably an MRI of the head and neck, should be performed to delineate the exact anatomy and diagnose the disease before any invasive contrast studies that may cause secondary infections. Secondary infection of the intraoral dermoid cyst may present with life-threatening airway obstruction; hence, prompt medical management is necessary. Complete surgical excision remains the mainstay of management, and histopathologic analysis confirms the diagnosis.

Declaration of patient consent

The authors certify that they have obtained all appropriate patient consent forms. In the form, the patient(s) has/have given his/her/their consent for his/her/their images and other clinical information to be reported in the journal. The patients understand that their names and initials will not be published and due efforts will be made to conceal their identity, but anonymity cannot be guaranteed.

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Conflicts of interest

There are no conflicts of interest.