Pilar Cysts: Symptoms, Causes, and Surgical Removal

Medically reviewed by Dr. Baraa Alnahhal, MD · Last reviewed: September 2026

Pilar cysts, also known as trichilemmal cysts or wens, are common, noncancerous growths that develop from hair follicles, primarily on the scalp. While usually painless and slow-growing, they can become uncomfortable if they rupture or grow large enough to press against the skull. Surgical removal is the standard treatment, offering relief for those concerned about discomfort or appearance.

What Is a Pilar Cyst?

A pilar cyst is a relatively rare, noncancerous (benign) growth that originates from the hair follicles. While these cysts can appear on the face, neck, arms, or legs, they are most frequently found on the scalp. Medically known as trichilemmal cysts or colloquially as "wens," they affect approximately 10% of the population, with women being more likely than men to develop them.

These cysts grow slowly and may not be noticed immediately. Over time, however, they can become quite large, sometimes reaching the size of a baseball. While they are not inherently dangerous, their size and location can lead to physical discomfort or self-consciousness regarding one's appearance. It is common for individuals to develop multiple pilar cysts over their lifetime.

Symptoms and Clinical Presentation

Pilar cysts typically present as smooth, flesh-colored lumps. They are often first discovered during routine activities such as washing or combing hair. Because they are slow-growing, a person may have a cyst for years before it becomes large enough to feel or see.

Clinical Feature	Description
Texture	Smooth, firm, and flesh-colored nodules.
Location	90% occur on the scalp; also found on the face, neck, and limbs.
Sensation	Usually painless; becomes painful if ruptured or pressed.
Growth Rate	Very slow, but can eventually reach significant sizes.
Multiplicity	Often occur in groups; having one increases the likelihood of others.

Causes and Pathophysiology

The development of a pilar cyst is a result of the body's natural skin cell renewal process going awry. Normally, old skin cells multiply and eventually fall off the skin's surface. A pilar cyst forms when these old cells and a protein called keratin become trapped beneath the epidermis, the skin's top layer.

As these trapped cells continue to multiply, they create layer upon layer of keratinized tissue, eventually pushing up the outer skin to form a visible lump. There is a strong hereditary component to pilar cysts; individuals with a family history of these growths are significantly more likely to develop them.

Pilar Cyst vs. Sebaceous Cyst

It is common for pilar cysts to be confused with sebaceous cysts, but they are distinct clinical entities with different origins and characteristics.

Feature	Pilar (Trichilemmal) Cyst	Sebaceous Cyst
Origin	Hair follicles (primarily on the scalp).	Sebaceous glands (found anywhere on the body).
Content	Keratin (protein for hair, skin, and nails).	Sebum (skin oil).
Appearance	Round, smooth, and can grow very large.	Tiny dome with a small opening (pore) on top.
Discharge	Usually none unless ruptured.	Oozes sebum if squeezed.

Diagnosis and Medical Evaluation

Healthcare providers typically diagnose pilar cysts through a physical examination of the affected area. The smooth, firm nature of the lump on the scalp is often a clear indicator. In specific cases, such as when a cyst grows exceptionally large or appears to involve underlying structures, a provider may order a CT or MRI scan to check the cyst's growth pattern or ensure it has not impacted the bones of the head. After surgical removal, the tissue is often examined under a microscope to confirm it is benign and not a rare proliferating trichilemmal tumor.

Treatment and Surgical Removal

The primary treatment for pilar cysts is surgical excision. Because these cysts do not resolve on their own and can potentially rupture or become infected, removal is often recommended for both medical and cosmetic reasons. The surgical process generally involves:

• Preparation: The area around the cyst may be shaved to provide clear access.

• Excision: The surgeon makes an incision and removes the cyst in its entirety.

• Closure: The site is closed with stitches to ensure proper healing.

• Recovery: Patients must keep the site clean to prevent infection. Signs of infection, such as a fever over 100.4°F or localized redness and warmth, require immediate medical attention.

Frequently Asked Questions

• What is a pilar cyst? A pilar cyst is a noncancerous, fluid-filled growth that develops from a hair follicle, usually on the scalp.

• Do pilar cysts hurt? They are usually painless but can become painful if they rupture or grow large enough to press against the skull.

• Can I pop a pilar cyst at home? No. Attempting to pop or slice a cyst can lead to serious infection and scarring.

• Is a pilar cyst the same as a sebaceous cyst? No. Pilar cysts grow from hair follicles and contain keratin, while sebaceous cysts grow from oil glands and contain sebum.

• Are pilar cysts hereditary? Yes, you may inherit the tendency to develop these cysts from your parents.

• Can pilar cysts become cancerous? It is extremely rare (about 3%), but they can occasionally form proliferating trichilemmal tumors.

• Will a pilar cyst come back after surgery? They can return, and individuals who have one are likely to develop new ones over time.

Conclusion

Pilar cysts are common, benign nuisances that are often inherited and slow to develop. While they are rarely a serious medical threat, their presence on the scalp can cause discomfort or self-consciousness. By understanding the nature of these cysts and opting for professional surgical removal, individuals can effectively manage the condition and prevent complications such as rupture or infection. If you have a new or growing lump on your scalp, contact a healthcare provider today for a professional evaluation and to discuss your options for removal.

This content is for informational purposes only and does not constitute medical advice. Always seek the advice of your physician or other qualified health provider with any questions you may have regarding a medical condition.