Multiple Trichilemmal Cysts of the Scalp in a Young Male.

Trichilemmal cyst (TC) is a benign cyst and is lined by stratified squamous epithelium that is derived from the outer root sheath. Middle-aged females are more commonly affected. It has close resemblance to epidermoid cyst and hence should be differentiated. We report a case of painful multiple TC on the scalp in a young male where a skin punch has been used as a therapeutic method.

INTRODUCTION

Trichilemmal cyst (TC) is benign adnexal tumor that arises from outer root sheath of the hair follicle. They affect 5-10% of the population with a female preponderance.[1] It usually presents as an asymptomatic firm nodule, which at times can be slightly painful. It is mainly seen in areas bearing hair follicle, mostly on the scalp.

CASE REPORT

A 24-year-old male presented with painful multiple, slow growing yellowish white swelling on the scalp. The first swelling that was asymptomatic appeared 3 years back which gradually progressed to involve multiple sites on the scalp. On examination of the scalp, there were four different sizes of swelling on the scalp [Figures 1–3] with largest of 2 cm × 1.5 cm and smallest around 1 cm × 1 cm in diameter. Histopathology revealed hyperkeratosis and acanthotic lining with stratified squamous epithelium. The cystic structure is identified in the dermis lined by squamous epithelium (only corneal layer is seen) with abrupt keratinization filling full cystic structure [Figures 4 and 5]. So a diagnosis of TC was made. Using a skin punch, multiple excision biopsy was done under perilesional local anesthesia containing 2% lignocaine with adrenaline followed by using a 3-0 nylon interrupted suture.

Figure 1

Swelling on the scalp

Figure 3

Multiple swellings on the scalp

Figure 4

Cystic structure is identified in the dermis lined by epithelium with abrupt keratinization filling full cystic structure (H and E ×5)

Figure 5

Cystic structure is identified lined by squamous epithelium (H and E ×40)

Close-up view of one of the swellings on the scalp

DISCUSSION

TC, also known as “pilar cyst,” is a benign cyst containing keratin and its breakdown products with a wall resembling external root sheath of hair.[1] It is commonly seen in middle-aged females, sometimes with autosomal dominant inheritance.[2] It presents as an asymptomatic or mildly painful, solitary, smooth, mobile, firm nodule, mainly over scalp[3] and rarely the face, trunk, and extremities may be involved.[4] TC may be commonly confused with epidermal cyst (EC) clinically.[5] Unlike EC, no punctum is seen.[4] TCs are lined by stratified squamous epithelial cells and contain homogenous eosinophilic material that show abrupt keratinization without an intervening granular layer. Lobules of squamous epithelium in the cyst wall suggest a proliferating trichilemmal cyst.[6] Thomas et al.[1] have also reported that excision can be done with smaller incisions because of the most firm nature of the cyst facilitating easy enucleation. In our case, we have used the method of excision biopsy using a skin punch followed by 3-0 nylon interrupted suture under perilesional local anesthesia. TC is often misdiagnosed as epidermoid cyst and hence TC should be kept as a differential diagnosis in a case of multiple swelling of the scalp. TC located on the scalp would cause pain easier through nerve pressure because of the presence of bony tissue located just beneath the cyst.[3] We report a case of multiple painful TC in a young male where a simple method of skin punch has been used as a therapeutic tool.

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Conflicts of interest

There are no conflicts of interest