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

The document discusses a common form of dermal cyst known as a pilar cyst or trichilemmal cyst. This cyst arises from the epithelium located between the sebaceous gland and the arrector pili muscle, and is filled with keratin. It is most commonly observed in young women and presents as a flesh-colored, smooth, movable, firm, and well-circumscribed nodule. In cases of long duration, hair loss on the skin surface immediately above the cyst may occur. Pilar cysts usually occur in areas with dense hair follicles, especially the scalp, but can also be found on the face, head, and neck. Diagnosis is mainly based on the clinical picture, and the treatment is radical surgical excision of the lesion, including the wall of the cysts.