Cystic Ear Lobe Mass

Epidermoid cyst has been known as the most common cutaneous cyst. These slow-growing lesions can be found anywhere in the body commonly head and neck. Disfigurement caused by this lesion is usually taken into consideration for early excision. It is also noteworthy, malignant transformation has been reported.


INTRODUCTION
Epidermoid cyst (EC) was first described by Roser in 1859 (1). Also known as epidermal cyst, epithelial cyst, keratin cyst, sebaceous cyst, milia, or epidermal inclusion cyst. They are benign, slow-growing cutaneous cyst derived from epidermis with a cystic enclosure of epithelium within the dermis layer which becomes filled with keratin and lipid-rich debris.
There are myriad theories which exists on its formation. Amongst others are formation from ectodermal tissue remnants which migrates via faulty pathway during embryogenesis, iatrogenic surgical or traumatic implantation of epithelial components or occlusion of pilosebaceous units (2). Male predilection especially within the 3 rd and 4 th decade of life has been noted, similar as in our case. It can be found practically anywhere in the body but common locations includes face, scalp, neck and trunk. EC comprises of 1.6 to 6.9 % of all head and neck mass. External ear epidermoid cyst are rare with only a few cases have reported involving the ear lobe(3).

CASE REPORT
A 20-year-old Indian gentleman with no prior medical illness presented with painless, left pinna swelling for the past 5 years. Patient claims swelling was slowly increasing in size over the years. There was however, no inciting trauma or infection prior to this. No otorrhea, otalgia, facial asymmetry, or any similar swelling elsewhere. Patient has no complain of hearing loss or imbalance. According to patient, no other family members have similar swelling. There was also no nasal or throat symptoms or any neck swelling.
Upon review, patient was comfortable with no obvious facial asymmetry noted. Pinna examination revealed soft, well-defined, smooth-surfaced, non-tender mass measuring 3 x 3 cm occupying posterior part of left ear lobe with no punctum or external skin changes. (Figure 1) In addition to that, left preauricular region revealed a sinus opening which was dry and non-tender. Right pinna examination was unremarkable. Other systematic examination was unremarkable. Patient was counselled for excision biopsy which he agreed upon. Intraoperatively, a cystic mass was removed in toto without difficulty and skin was closed. Cystic mass was sent for histopathological examination which revealed cystic cavity lined by stratified squamous epithelium with keratin production which is suggestive of epidermoid cyst.

What is your diagnosis?
Answer: Left ear lobe epidermoid cyst

DISCUSSION
As for the presentation, EC remains asymptomatic until it becomes infected. Diagnosis is usually by clinical examination and via ultrasonography to confirm its cystic nature. Nonetheless, histopathological examination of the excised mass is the gold standard. Recurrence post excision is considered to be rare. Differential diagnosis of ear lobe mass incudes lipoma, hemangioma and pseudocyst. EC has been linked with certain hereditary syndromes including Gardner syndrome, basal xell nevus syndrome and panchyonchia congenital.
Albeit rare, malignancy involving EC has been reported, namely basal cell carcinoma, squamous cell carcinoma, Bowen's disease (4). Squamous cell carcinoma developing from an EC ranges from 0.011 to 0.045 %. It is prudent for all physicians to be aware that although epidermoid cyst is a common cutaneous cyst and clinical diagnosis may be sufficient, it is imperative to bear in mind of its risk of malignant transformation. Hence, we would recommend that all cysts should be sent for histopathological examination for evaluation.