From the Research
Pilar cysts typically follow a benign clinical course characterized by slow, asymptomatic growth over months to years. These cysts, also known as trichilemmal cysts, commonly develop on the scalp but can appear elsewhere on the body, as seen in a case report of a pilar cyst in the left temporal region 1. They present as firm, mobile, dome-shaped nodules beneath the skin, usually ranging from 0.5 to 5 cm in diameter. Most pilar cysts remain asymptomatic, though some patients may experience tenderness if the cyst becomes inflamed or infected. Complications are uncommon but can include rupture, infection, or rarely, malignant transformation into a proliferating trichilemmal tumor. If a pilar cyst becomes infected, it may present with redness, pain, and swelling, potentially requiring antibiotics. The definitive treatment for symptomatic or cosmetically concerning pilar cysts is complete surgical excision, which prevents recurrence by removing the entire cyst wall, as supported by a study on the removal of keratinous and pilar cysts with the punch incision technique 2. Simple drainage without complete excision typically leads to recurrence. These cysts develop from the outer root sheath of hair follicles, which explains their predilection for hair-bearing areas and their characteristic thick, keratinous contents. Patients should be advised that multiple pilar cysts can occur, particularly in those with a family history, as there is an autosomal dominant inheritance pattern in some cases.
Some key points to consider in the clinical course of pilar cysts include:
- They are benign lesions that arise from the hair follicle epithelium 1
- They can occur in various locations, including the scalp, head, and neck region 1
- They can be mistaken for other conditions, such as temporal space infection or laryngocele 1, 3
- Histologic diagnostic difficulties may arise in certain situations, such as acute inflammation or epithelial remnants 4
- The morphological spectrum of pilar cysts can vary, including non-neoplastic and neoplastic forms 5
The most effective treatment for pilar cysts is complete surgical excision, which can be performed using various techniques, including the punch incision technique 2. This approach prevents recurrence by removing the entire cyst wall and is recommended for symptomatic or cosmetically concerning pilar cysts.