A 43-Year-Old Woman with a Solitary, Asymptomatic Nodule on the Scalp

Abstract

Pilar cyst, also known as trichilemmal cyst, is a common form of dermal cyst. It arises from the epithelium located between the sebaceous gland and the arrector pili muscle. Pilar cyst is lined by stratified squamous epithelium without a granular cell layer and is filled with keratin. It is most commonly observed in young women. Clinically, pilar cyst presents as flesh-colored, smooth, movable, firm, and well-circumscribed nodule. In case of long duration, hair loss on the skin surface immediately above the cyst may be presented. Most commonly, they are multiple lesions, but sometimes, single lesion might be presented. Pilar cyst usually occurs in areas with dense hair follicle especially the scalp, but they may also be found on the face, head, and neck. Diagnosis of pilar cysts is mainly based on the clinical picture. The treatment is radical surgical excision of the lesion including the wall of the cysts.