J.Sales-Llopis

Neurosurgery Service, Alicante University General Hospital, Alicante, Spain.

A trichilemmal cyst, also known as a pilar cyst, is a common benign cyst that develops within the hair follicles. It typically occurs on the scalp but can also be found on other parts of the body. Trichilemmal cysts are usually smooth, round, and mobile under the skin. They are filled with keratin, a proteinaceous material that gives hair, nails, and skin their structure. These cysts are typically non-cancerous and do not cause any symptoms unless they become infected or enlarge significantly. Treatment usually involves surgical removal of the cyst to prevent recurrence or complications.

Pilar cysts are relatively rare benign cysts that grow from your hair follicles. Most pilar cysts surface on your scalp (head), but they can appear on your face, neck, arms and legs. Pilar cysts are sometimes called trichilemmal cysts or wens. Healthcare providers use surgery to remove cysts.

While pilar cysts (trichilemmal cysts) are generally harmless, they can occasionally lead to complications. Some possible complications associated with pilar cysts include:

Rupture: Pilar cysts can rupture, leading to the release of the cyst contents into the surrounding tissue. This can cause inflammation, pain, and potentially an increased risk of infection.

Recurrence: Although rare, pilar cysts have a tendency to recur after removal. If the entire cyst sac is not completely removed during surgical excision, the cyst can regrow over time.

Cosmetically bothersome: Depending on their location and size, pilar cysts can be cosmetically bothersome, particularly if they are visible or cause irregularities on the skin surface.

It's important to note that these complications are relatively uncommon.

A pilar cyst infection can occur when bacteria enter the cyst, leading to inflammation and symptoms such as pain, redness, swelling, and increased tenderness at the cyst site. The infection can occur due to a break in the skin over the cyst or as a result of self-manipulation or trauma to the cyst.

Skull osteomyelitis from a infected pilar cyst