 Abstract | | |
Background: Epidermoid cysts (ECs) are uncommon benign cystic lesions derived from the germinative epithelium. Head and neck ECs constitute only 7% of all ECs whereas only 1.6% are seen intraorally. The floor of the mouth is the commonest intraoral site whereas tongue, lips, buccal mucosa, and jaws are less commonly involved intraoral sites. To date, very few large case series of ECs of head and neck have been published. To the best of our knowledge, this is the third-largest case series of 11 intraoral ECs along with 2 extra-oral cases in the pre-auricular region. Aims: To highlight the typical and atypical features of ECs in the common as well as rare sites and draw attention to its consideration as a differential diagnosis for head and neck masses. Settings and Design: Archival data of 13 histopathological cases identified as ECs were analyzed from the Department of Oral Pathology at a tertiary dental hospital and college in New Delhi from 2007 to 2020. Materials and Methods: The demographic, clinical, radiographic, histopathological features, and treatment modalities were recorded and analyzed. Statistical Analysis Used: Appropriate statistical tests were used. Results: The study found strong male predilection in the ratio of 10:3 with an average age of presentation as 28 years. The pre-auricular region and floor of the mouth were the common sites involved followed by buccal mucosa, lips, and jaws. All patients presented with slowly growing swelling with dysphagia, dyspnea, and dysphonia seen in larger cysts on the floor of the mouth. Microscopically, all cases were lined with stratified squamous epithelium filled with laminated layers of keratin. Two cases showed the presence of melanin. One case showed recurrence even after complete surgical excision. Conclusion: ECs, though a rare entity, should be considered in differential diagnosis for head and neck masses and require close follow-up due to their potential for malignant transformation.
Keywords: Differential diagnosis, epidermoid cysts, head and neck, intraoral, keratin
How to cite this article:
Kumar P, Malhotra R, Urs AB, Augustine J, Mohanty S. Epidermoid cysts of the orofacial region: A clinico-pathological study of 13 cases with review of literature. Indian J Pathol Microbiol 2023;66:568-72 |
How to cite this URL:
Kumar P, Malhotra R, Urs AB, Augustine J, Mohanty S. Epidermoid cysts of the orofacial region: A clinico-pathological study of 13 cases with review of literature. Indian J Pathol Microbiol [serial online] 2023 [cited 2023 Sep 27];66:568-72. Available from: https://www.ijpmonline.org/text.asp?2023/66/3/568/368571 |
| Introduction | |  |
Epidermoid cysts (ECs), also termed as epithelial, keratinous, sebaceous, or infundibular cysts, are developmental cysts originating from the germinative epithelium.[1],[2] They develop from abnormal epithelial components of ectodermal tissue formed during the fetal period (congenital cysts), or implanted epithelium arising after surgery or trauma (acquired cysts).[2],[3],[4] Meyer in 1955 found three histopathological variants, epidermoid (lined with simple squamous epithelium), dermoid (when skin adnexa are found in the cyst wall), or teratoid (when tissues of all three germ layers, such as muscle, cartilage, and bone are present).[5] The majority of the ECs are reported in ovaries and testicles (80%); with the head and neck region constituting 7% of the cases. 1.6% cases are found in the oral cavity, accounting for 0.01% of all the cysts of the oral cavity.[1],[6]
ECs are indolent in nature, slow to progress, and mostly remain asymptomatic. The larger cyst may cause dyspnea and dysphagia. They are commonly observed during the second and third decades of life with a greater prevalence in men.[7],[8] Commonly involved site in head and neck region is the external third of the eye-brow (43%) followed by the floor of the mouth (23%).[9] Cases of ECs in locations, such as the lip, buccal mucosa, tongue, pre-auricular region, and intraosseously within the mandible and maxilla are very rare.[10] The aim of the present series of 13 cases of ECs is to highlight its typical and atypical presentation in the common as well as rare sites and draw attention to its consideration as a differential diagnosis for head and neck masses.
| Materials and Methods | | |
This is a retrospective observational study. Archival data of 13 histopathological proven cases of ECs from 2007 till 2020 were retrieved from the files of the Department of Oral Pathology at a tertiary dental hospital and college in New Delhi from 2007 to 2020. Informed consent from the required patients was obtained. Complete relevant demographic, clinical, radiographic, and histopathological data were recorded. Clinical features such as age, sex, site, duration of the lesion, and presenting features were analyzed. Image findings on orthopantomograph and MRI were studied in required cases. 3–4 μm thick sections of paraffin-embedded tissue of each case were stained with hematoxylin and eosin and reviewed by three oral pathologists independently.
| Results | | |
The mean age at diagnosis in the present series of 13 cases of ECs was 28 years with a range of 15 to 48 years. A strong male predilection in the ratio of 10:3 was found. Out of 13 cases, 2 were present extra-orally while the rest were located intraorally. Both the cases of extra-oral ECs were located in the pre-auricular region. The floor of the mouth was the most commonly involved intraoral site. Two cases each were noted on the rare intraoral sites like buccal mucosa, lip as well as intraosseously within the ramus area of the mandible. All patients presented with slowly growing swelling, eight of them were associated with pain. One case showed draining puncta on the buccal mucosa. Microscopically, all cases were lined with stratified squamous epithelium filled with laminated layers of keratin. One case showed recurrence within 6 months even after complete surgical excision. The clinical and radiographic results are summarized in [Table 1].
| Discussion | | |
Roser, in 1859, first described EC.[11] It is the most common cutaneous cyst, which is rarely observed in the head and neck region and is even rarer in the oral cavity. Few case series of ECs in the head and neck region, specifically the orbital region, are available in the published literature.[12],[13] But only single case reports of intraoral EC are reported with very few case series. To the best of our knowledge, this is the third-largest case series of 11 intraoral ECs along with 2 extra-oral cases in the pre-auricular region. Moreover, earlier case series are confined to ECs on the floor of the mouth,[10],[14] whereas the present series includes cases found in sites not common for EC like lips, buccal mucosa, pre-auricular region, and jaws.
EC may arise due to entrapment of pluripotent cells or as a result of implantation of epithelium.[10],[15] Mechanism of EC development within the oral mucosa can be explained in three ways: First, the epithelium may be sequestrated in lines of fusion during the embryonic process or the epithelial tissue may be implanted in the tissues in a traumatic manner. Second, aberrant pilar differentiation of mucosal keratinocytes could be a possible mechanism. Finally, the epithelial proliferation of adjacent hair follicle origin cells can infiltrate the mucosal skin area through the subcutaneous tissue.[16] In this case series, there was one case in the pre-auricular region that was associated with previous iatrogenic trauma (incision and drainage due to repeated pus discharge), and thus could be implanted in nature.
In the oral cavity, these cysts occur most frequently on the floor of the mouth with occasional occurrence on the tongue, buccal mucosa, lips, or in the jaws.[9],[10] We found maximum cases on the floor of the mouth (4 cases) followed by buccal mucosa (3 cases) and equal occurrence on the lip, pre-auricular region, and within the jaws (2 cases each). The differential diagnoses of a clinically benign cystic lesion in the head–neck region include an array of developmental and acquired lesions. Differential diagnosis of such lesions on buccal mucosa includes lipoma, fibroma, infectious processes of odontogenic origin affecting the facial spaces of the masseter and buccinator muscles, benign salivary gland neoplasm, lymphoepithelial cysts, dermoid cysts, mucocele, and foreign body granulomatous reactions.[17] Differential for an EC on the floor of the mouth should include other common lesions like thyroglossal duct cyst, ranula, cystic hygroma, mucocele, branchial cleft cyst, hemangioma, and infective lesions.[18] For such lesions on the lip, we should consider other possibilities like mucocele, fibroma, hemangioma, schwannoma, or granulomatous lesion.[19] For lesions in the pre-auricular region, we should consider salivary gland neoplasm and space infection as other possibilities.[20] For radiolucent lesions in the mandible, we should include more common lesions like odontogenic cysts.
ECs occur frequently in patients between 15 and 35 years but can be seen in all age groups. These are slow-growing asymptomatic masses but once they increase in size, they can cause esthetic and functional impairment.[21],[22] Most authors suggest equal gender predilection with few authors suggesting male preponderance.[23] We found similar clinical results with a mean age of occurrence as 28 years with a strong male predilection in the ratio of 10:3. The smaller cysts were mostly asymptomatic while the larger cysts, especially on the floor of the mouth, caused dysphagia, dyspnea, and dysphonia.
The size and location of the EC are the cause of varied clinical manifestations. The size is variable, ranging from a few millimeters to a few centimeters, but when the size exceeds 5 cm, it is referred to as a giant EC.[24] There are three reported cases of giant ECs within the oral cavity in the literature, one of 7 cm and two of 13 cm.[25],[26] In our series, the diameter of the cysts ranged from 0.5 to 7.0 cm, with one case having a size 5 × 7 cm. EC of the floor of the mouth developing above the mylohyoid muscle has the potential to displace the tongue toward the palate and subsequently create difficulty with mastication, speech, and possibly breathing. Cysts developing below the mylohyoid often produce submental or submandibular swelling.[27] In our series, out of the three cases on the floor of the mouth, two were present above the mylohyoid muscle while one of them perforated the mylohyoid muscle. All of them caused functional difficulties like dysphagia, dyspnea, and dysphonia.
Imaging has an important role in confirming the diagnosis of EC. Ultrasound is the initial imaging modality. ECs are seen as well-defined cysts with multiple well-defined dependent echogenic nodules within the cyst. Magnetic resonance imaging (MRI) shows fluid signals due to high protein content, and the areas of the fat component will show low signals on fat-suppressed images. MRI facilitates visualization of the exact location and extent of cystic lesions on the floor of the mouth and is useful for determining their relationship to the surrounding muscles.[28] Orthopantomographs of two intraosseous cases in the mandibular ramus revealed well-defined unilocular radiolucency. MRI of cysts in the floor of the mouth revealed homogenous hypodense lesions.
Gross specimens of all cases showed cheesy, tan, yellow, white material with thick fibrous cyst wall. Many of them contained thick yellow cystic fluid [Figure 1]. These are often described as pearly tumors because of the shiny smooth waxy character of the dry keratin on gross inspection.[29] Histopathological examination of all cases revealed a cystic cavity lined by orthokeratinized stratified squamous epithelium of 4–8 cell layers with a prominent granular layer [Figure 2]a. Cystic lumen showed abundant keratin arranged in a laminar pattern [Figure 2]b. The cystic wall was composed of dense bundles of collagen intervened by fibroblasts and blood vessels. In a study from the Indian population, 63% of the cysts showed melanin pigmentation.[30] We found melanin pigmentation within the epithelium in three cases [Figure 2]c. | Figure 1: Gross features of various cases on macroscopic examination. (a) Thick cheesy yellow fluid containing keratin within the cyst. (b) Cut surface of cyst showing thick yellow solid content along with the thick fibrous capsule. (c) Intact round to ovoid epidermoid cyst white in color
Click here to view |
 | Figure 2: Histopathological features of various cases on microscopic examination. (a, H and E, × 4) Cystic lining composed of hyperorthokeratinized stratified squamous epithelium with abundant keratin in the lumen. (b, H and E, × 10) Intraluminal keratin arranged in laminar pattern. (c, H and E, × 40) Melanin pigmentation in the basal cell layer
Click here to view |
Total excision is the main treatment modality for intraoral epidermal cystic lesions. Marsupialization is another alternative for the management of large cysts. Lesions above the mylohyoid muscles are operated intraorally, whereas those below the muscle are removed via an incision in the neck.[22] All the cases in the present series were surgically excised.
The prognosis of EC is good with a recurrence rate <3%. Although ECs are benign, few cases of transformation into malignancies have been reported. Rare cases of premalignant and malignant conditions (Bowen's disease, Paget's disease, squamous cell carcinoma, and basal cell carcinoma) have been found in their walls.[1] In our case series, we found recurrence in one case within 6 months of excision. None of the cases showed malignant transformation in the follow-up period.
| Conclusion | | |
ECs are a rare entity in the head and neck region and even rarer intraorally. These are slow-growing asymptomatic masses but once they increase in size, they can cause considerable disfigurement of the head and neck region. They must be considered in the differential diagnosis of a lump or a mass and require close follow-up due to their potential for malignant transformation.
All the authors have made
(1) substantial contributions to conception and design of the study, acquisition of data, or analysis and interpretation of data and in (2) drafting the article.
Declaration of patientconsent
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.
Ethics
The study has been approved by Institutional Ethical Committee.
Authors contribution
All authors have contributed equally.
Financial support and sponsorship
Nil.
Conflicts of interest
There are no conflicts of interest.
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Correspondence Address:
Rewa Malhotra
Maulana Azad Institute of Dental Sciences, MAMC Complex, Bahadur Shah Zafar Marg, New Delhi - 110 002
India
 Source of Support: None, Conflict of Interest: None  | Check |
DOI: 10.4103/ijpm.ijpm_1193_21
[Figure 1], [Figure 2]
[Table 1] |
