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 Table of Contents  
Year : 2016  |  Volume : 28  |  Issue : 1  |  Page : 86-89

Epidermoid cyst in lower lip mimicking mucocele: A rare entity with review of literature

1 Department of Oral Medicine and Maxillofacial Radiology, Triveni Institute of Dental Sciences, Hospital and Research Centre, Bilaspur, Chhattisgarh, India
2 Department of Oral Medicine and Maxillofacial Radiology, Kamineni Institute of Dental Sciences, Narketpally, Telangana, India

Date of Web Publication8-Sep-2016

Correspondence Address:
Ketaki Kinikar
Department of Oral Medicine and Maxillofacial Radiology, Triveni Institute of Dental Sciences Hospital and Research Centre, Bilaspur - 495 002, Chhattisgarh
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Source of Support: None, Conflict of Interest: None

DOI: 10.4103/0972-1363.189987

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An epidermoid cyst is the most common cutaneous cyst, which is rarely observed in the oral cavity. Epidermoid cysts are the result of the proliferation of the surface epidermal cells within the dermis, which may occur anywhere in the body; however, approximately 6.9% are found in the head and neck region, with less than 0.01% incidence of all oral cavity cysts. In this report, we present a rare case of a labial epidermoid cyst in a 27-year-old woman with complaints of swelling and facial asymmetry in the lower lip beneath the left commissure for 3 years.

Keywords: Dermoid cyst, epidermoid cyst, keratin, labial mucosa

How to cite this article:
Kinikar K, Meduri V, Tejasvi A, Bhayya H. Epidermoid cyst in lower lip mimicking mucocele: A rare entity with review of literature. J Indian Acad Oral Med Radiol 2016;28:86-9

How to cite this URL:
Kinikar K, Meduri V, Tejasvi A, Bhayya H. Epidermoid cyst in lower lip mimicking mucocele: A rare entity with review of literature. J Indian Acad Oral Med Radiol [serial online] 2016 [cited 2022 Nov 28];28:86-9. Available from: http://www.jiaomr.in/text.asp?2016/28/1/86/189987

   Introduction Top

Epidermoid and dermoid cysts are benign lesions encountered throughout the body, particularly in areas where embryonic elements fuse together. Dermoid and epidermoid cysts are also observed in the head and neck region with an incidence ranging from 1.6 to 6.9%; both cysts are reported in less than 0.01% of all oral cavity cysts.[1] In the oral cavity, these cysts occur most frequently in the area of the floor of the mouth and may also occur on the tongue, lips, or the interior of the bone.[2] Cases of epidermoid cyst in locations, such as the lip, are very rare. On reviewing English literature in PubMed and Google databases, 11 cases were noted, out of which 8 were reported in the lower lip and 3 in the upper lip. In this report, we describe a 27-year-old female patient with a labial epidermoid cyst.

   Case Report Top

A 27-year-old woman presented with a 3-year history of a lump on the lower lip. Initially, the lump was smaller in size and gradually enlarged to the present size. Otherwise, she had no notable family history or medical history. Extraoral examination revealed a solitary, roughly spherical swelling approximately 2 × 2 cm in size seen beneath the lower lip on the left side extending medially 1 cm away from the midline to laterally up to the corner of the mouth, superiorly from the vermillion border of the lower lip and inferiorly up to 1.5 cm above the inferior border of the mandible [Figure 1]. The overlying skin appeared to be normal and smooth. The lesion was firm in consistency, freely movable, noncompressible, nonreducible, nontender, and no pulsations were felt. The intraoral examination of the lower labial mucosa revealed a solitary swelling, which was roughly spherical and approximately 2 × 2 cm in size, which was extending medially 1 cm from the labial frenum to laterally 1 cm away from the left commissure, superiorly up to the mucosal lining of the lower lip to inferiorly up to the labial vestibule [Figure 2]. The swelling was nontender to palpation, did not blanch on pressure, and formed a doughy, freely mobile mass. The overlying mucosa was normal in color and texture. All the complement of teeth were present and the patient's oral hygiene was satisfactory. A differential diagnosis of lipoma and epidermoid cyst was made. Ultrasound was performed which revealed a well-defined hypoechoic lesion measuring 2.1 × 1.0 cm within the subcutaneous plane of the left lower lip region. Few internal echoes were noted within the lesion, which was suggestive of keratin plugs. Fine-needle aspiration cytology (FNAC) was done which showed abundant nucleate and anucleate squamous cells with marked acute inflammatory infiltrate [Figure 3], and an impression of “infected keratinous cyst” was made. On the basis of clinical and other available diagnostic data, the cyst was enucleated under local anesthesia, and the specimen was sent for histopathological examination, which revealed a cystic cavity lined by stratified squamous epithelium with rete ridges at one end whereas no epithelium was seen at the other end in a scanty connective tissue stroma [Figure 4]. Superficial epithelium showed the presence of keratin flecks within the lumen of the cyst. Mild chronic inflammatory cell infiltration was seen within the connective tissue stroma, which was suggestive of a “simple epidermoid cyst.”
Figure 1: An extraoral swelling beneath the vermilion border of the left lower lip

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Figure 2: Palpable cystic mass measuring 2 × 2 cm on the lower labial mucosa

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Figure 3: Cytological image showing abundant anucleate and nucleate squamous cells with marked acute inflammatory infiltrate

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Figure 4: (Hematoxylin and eosin 100×) Photomicrograph showing the cystic cavity lined by stratified squamous epithelium with rete ridges, keratin flecks within lumen, and mild chronic inflammatory cell infiltration into the connective tissue stroma

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   Discussion Top

Epidermoid cysts have a cystic cavity that is lined by an epithelium without skin appendages. Epidermoid cysts may be classified as congenital or acquired even if there is no difference between the two in presentation or histological appearance. These cysts have been sparsely reported in oral and perioral locations. Mechanism of these cysts on the oral mucosa can be explained in three ways: first, displaced epithelial aggregation can occur secondary to trauma. This is called as “implantation phenomenon,” and this implanted cell may then proliferate and develop a cyst.[3] Second, aberrant pilar differentiation of mucosal keratinocytes could be considered a hypothetical avenue of pathogenesis. Finally, epithelial proliferation of adjacent hair follicle origin cells can infiltrate the mucosal skin area through subcutaneous tissue.[4] Implantation cysts are also referred to as “post-traumatic cyst” because they are believed to originate through implantation of epithelium by either surgical or accidental trauma into deeper mesenchymal tissues.[5]

On literature review using PubMed and Google databases, 10 cases of epidermoid cyst in the lip region were noted till date [Table 1]. Most patients with epidermoid cyst were in the range of 10–35 years of age, and were predominantly males.[6] These cysts grow slowly and painlessly. All of the previously reported cases exhibited a firm, fluctuating swelling. They are often described as pearly tumors because of a shiny smooth waxy character of the “dry keratin” on gross inspection.
Table 1: English literature review till date

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Lip contains adipose tissue, connective tissue, blood vessels, nerves, and salivary glands, and hence, any lesion that may originate from these components may occur in lips. A differential diagnosis of odontogenic infection, mucocele, lipoma, hemangioma, and lymphangiomas can be considered. Epidermoid cyst rarely discloses malignancy. Lopez-Rios et al. described a patient with squamous cell carcinoma arising in the wall of a conventional epidermoid cyst.[17] Surgical enucleation is the only effective treatment for these types of lesions. Prognosis is very good with a very low incidence of relapse. Postoperative complications are rare and are reduced by closely following the capsule and its complete removal.

   Conclusion Top

When compared to other cystic lesions in the oral cavity, epidermoid cysts are quite rare and their diagnosis and long-term follow-up are important because a minimal percentage of them have potential for malignancy in the long run.

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Conflicts of interest

There are no conflicts of interest.

   References Top

Ozan F, Polat HB, Ay S, Goze F. Epidermoid Cyst of the Buccal Mucosa: A Case Report. J Contemp Dent Pract 2007;8:90-6.  Back to cited text no. 1
Worley CM, Laskin DM. Coincidental sublingual and submental epidermoid cysts. J Oral Maxillofac Surg 1993;51:787-90.  Back to cited text no. 2
Walstad WR, Solomon JM, Schow SR, Ochs MW. Midline cystic lesion of the floor of the mouth. J Oral Maxillofac Surg 1998;56:70-4.  Back to cited text no. 3
Perez LM, Bruce JW, Murrah VA. Trichilemmal cyst of the upper lip. Oral Surg Oral Med Oral Pathol Oral Radiol Endod 1997;84:58-60.  Back to cited text no. 4
King ES. Post-traumatic epidermoid cysts of hands and fingers. Br J Surg 1933;21:29-43.  Back to cited text no. 5
Ettinger RL, Manderson RD. Implantation keratinizing epidermoid cysts: A review and case history. Oral Surg Oral Med Oral Pathol 1973;36:225-30.  Back to cited text no. 6
Rule DC. Dermoid cyst of the lower lip: A case report. Br J Oral Surg 1976;12:116.  Back to cited text no. 7
Papanayotou PH, Kayavis JG. Epidermoid implantation cyst of the lower lip: Report of a case. J Oral Surg 1977;35:585-6.  Back to cited text no. 8
Wang WC, Lin LM, Shen YH, Lin YJ, Chen YK. Concurrent extravasation of mucocele and epidermoid cyst of the lower lip: A case report. Kaohsiung J Med Sci 2005;21:475-9.  Back to cited text no. 9
Moritani N, Mishima K, Yamada T, Nakano M, Kondo S, Sugahara T. A case of epidermoid cyst in the upper lip. Japanese Journal of Oral and Maxillofacial Surgery 2007;53:353-7.  Back to cited text no. 10
Shin JB, Son SW, Kim IH. Epidermal Cyst on the Lower Lip. Ann Dermatol 2007;19:112-4.  Back to cited text no. 11
Sable D, Jha PK. A rare case of epidermoid cyst on the lower lip. Journal of Pearldent 2010;1:13-7.  Back to cited text no. 12
Amorim RFB, Rosa EA, Lima RBA, Stypulkowski RP, Cunha GLQA. Epidermoid cyst in the lower lip – An atypical clinical presentation. Oral Surg Oral Med Oral Pathol Oral Radiol 2012;114:e130-1.  Back to cited text no. 13
Shetty YN. An unusual case of epidermoid cyst of the lower lip - A case report. Journal of Pearldent 2013;4:43-5.  Back to cited text no. 14
Dogan F, Bucak IH. Congenital epidermoid cyst results in muscle fusion defect in the upper lip. Case Reports in Otolaryngology 2014;2014:Article ID 540910.  Back to cited text no. 15
Phukan JP, Sinha A, Pal S, Jalan S. Cytodiagnosis of epidermoid cyst of the upper lip: A common lesion in an uncommon site. Journal of Laboratory Physicians 2014;6:60-2.  Back to cited text no. 16
López-Ríos F, Rodríguez-Peralto JL, Castaño E, Benito A. Squamous cell carcinoma arising in a cutaneous epidermal cyst: Case report and literature review. Am J Dermatopathol 1999;21:174-7.  Back to cited text no. 17


  [Figure 1], [Figure 2], [Figure 3], [Figure 4]

  [Table 1]


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