Int. J. Life. Sci. Scienti. Res., 4(5): 1522-1526, September 2018

 

Large Post Auricular Epidermal Inclusion Cyst Involving Facial Nerve-A Rare Case Report

 

Preeti Singh¹*, Vishal Pathania², Kamal Goyal³

 

¹Assistant Professor, Department of ENT, SGT Medical College and Hospital Gurgaon, India

²Professor, Department of ENT, SGT Medical College and Hospital Gurgaon, India

³Senior Resident, Department of ENT, Medical College and Hospital Gurgaon, India

 

^*Address for Correspondence: Dr. Preeti Singh, Assistant Professor, Department of ENT, SGT Medical College, Farukhnagar Road, Budhera Village, Gurgaon -122505, India

 

ABSTRACT- Epidermoid cysts represent most common benign, cutaneous cysts. Most frequently was seen on face, scalp, and trunk. It accounts for approximately 80% of follicular cyst of skin. Epidermoid cyst usually remains asymptomatic until it gets secondarily infected. Malignant changes are seen very rarely. We describe a case of the huge post auricular epidermoid cyst, which was encasing extra-temporal part of the facial nerve and was in close proximity to external carotid artery. The cyst was excised surgically and histopathology confirmed the diagnosis of epidermoid cyst.

Key words: Epidermoid cyst, Post-auricular cyst, Fine Needle Aspiration Cytology, FNAC

 

INTRODUCTION- Fourteen years old male patient presented with a complaint of swelling behind right ear in ENT department SGT Medical College and Hospital Gurgaon, Haryana in May 2018. On the basis of clinical examination, FNAC findings and CT scan findings, diagnosis of epidermal inclusion cyst was made. With the diagnosis of epidermal inclusion cyst patient planned for excision of the cyst under GA. During surgery Lower part of the cyst was found adherent to facial nerve, cyst was dissected carefully to avoid any damage to the nerve sheath. Post-operatively histopathological examination of cyst confirmed the diagnosis of epidermal inclusion cyst. Epidermal inclusion cyst is a benign cystic lesion which usually occurs due to proliferation and implantation of epidermal elements within a circumscribed space in the dermis ^[1].  Epidermal cysts of post-auricular region are rare, with few cases described in the literature. They should be differentiated from lipoma and haemangioma. Lipomas are benign tumors which composed of fatty tissues and hemangiomas are often present at birth ^[2].  

 

CASE REPORT- Fourteen years old male patient presented with a complaint of swelling right post auricular region for 4 months. Initially, it was small in size and increased gradually to reach the present size of 4x3 cm. It was painless and not associated with any other symptoms. No familial history suggestive of similar swellings.

On examination, the swelling was about 4 x 3 cm, soft to cystic in consistency, non-tender, nonpedunculated and partly mobile skin over swelling normal, no rise of regional temperature, no regional lymph node involvement. There was no discharging sinus or pointing abscess. Pinna, external auditory canal, tympanic membrane and facial nerve on the right side were absolutely normal. On the basis of clinical examination differential diagnosis of swelling included epidermoid cyst, sebaceous cyst, lipoma, dermoid cyst and neurofibroma fine needle aspiration cytology suggestive of epidermal inclusion cyst (sebaceous cyst or epidermoid cyst). Contrast-enhanced CT (CECT) neck was done to know the extent of cyst interiorly, inferiorly and to rule out the intracranial extension.

 

Fig. 1: NCCT Temporal bone axial cuts

 

With the diagnosis of epidermal inclusion cyst, the patient was planned for complete surgical excision of mass under general anaesthesia. The Swelling had well-defined cyst wall and contained foul smelling soft cheesy material with the characteristic cheesy smell. Intraoperatively Lower part of the cyst was found adherent to the facial nerve, the cyst was dissected carefully to avoid any damage to the nerve sheath.

 

 

Excised mass sent for histopathological examination.

 

Fig. 4: Macroscopic picture of dissected cyst

 

The macroscopic picture consists of cystic bag with soft cheesy material and microscopic picture consist of stratified squamous epithelium with the presence of numerous keratin flakes and underlying thin connective tissue capsule with collagen bundles and blood vessels. Histopathology confirmed the diagnosis of epidermoid cyst.

 

Fig. 5: Microscopic picture shows epithelial lining with keratin flakes

 

DISCUSSION- The epidermal inclusion cyst is a benign cystic lesion, which usually occurs due to proliferation and implantation of epidermal elements within a circumscribed space in the dermis ^[1]. Epidermal cyst is also called sebaceous, keratin cyst, epithelial cyst or milia or epidermal inclusion cyst. Usually formed by incorrect migration of remnants of ectodermal tissue during embryogenesis or by traumatic and surgical implantation of epithelial components ^[3]. The epidermoid cyst can occur in any part of the body but commonly involve face, scalp, neck and trunk ^[4]. Commonly occurs in 3^rd and 4^th decades of life with slight male preponderance ^[5]. The epidermal cysts are usually asymptomatic but sometimes due to secondary infection, they become inflamed. Malignant changes are rare and include epidermal cell carcinoma, Bowen’s disease, and melanoma in-situ ^[6].

Epidermal cysts of post-auricular region are rare, with few cases described in the literature. They should be differentiated from lipoma and haemangioma. Lipomas are benign tumors which composed of fatty tissues and hemangiomas are often present at birth ^[2].

We are reporting this case because huge post auricular cyst with uncommon age of presentation (14 years), most common age of presentation of epidermoid cyst is 3^rd and 4^th decades ^[5]. Cyst was adherent to the facial nerve and was in close proximity to carotid which is again a rare presentation. The lesion was excised without damaging the facial and no recurrence was seen in 6 months post-operative period.

 

CONCLUSIONS- Cystic swelling in post auricular region may involve the facial nerve anteriorly so that while operating we should be very precise to preserve the facial nerve.

 

CONTRIBUTION OF AUTHORS

Dr Preeti Singh- Data collection and analysis, Research concept and design.

Dr Vishal Pathania- Research concept and design, Supervision.

Dr Kamal Goyal- Data collection and analysis

 

REFERENCES

1.      Lam SY, Kasthoori JJ, Mun KS, Rahmat K, Epidermal inclusion cyst of breast: A rare benign entity. Singapore Med J., 2012; 51: e191-4.

2.      Dive AM, Khandekar S, Moharil R, Deshmukh S.  Epidermoid cyst of the outer ear: A case report and review of literature. Indian Journal of Otology, 2012; 18: 34-37.

3.      Hong SH, Chung HW, Choi JY, Koh YH, Choi JA, Kang HS. MRI findings of subcutaneous epidermal cysts: emphasis on the presence of rupture. Am J Roentgenol, 2006; 186: 961-966.

4.      Handa U, Kumar S, Mohan H. Aspiration cytology of epidermoid cyst of terminal phalanx. Diagn cytopathol, 2002; 26: 266-267.

5.      Perez-Guisado J, Scilleta A, Cabrera-Sanchez E, Rioja LF, Perotta R. Giant earlobe epidermoid cyst. Journal of cutaneous and aesthetic surgery, 2012; 5: 38-39.

6.      Swygert KE, Parrish CA, Cashman RE, Lin R, Cockerell CJ. Melanoma in situ involving an epidermal inclusion (infundibular) cyst. AM J Dermato. Pathol, 2007; 29: 564-565.