The Difference Between a Pilonidal and Sebaceous Cyst
As one of the most common abnormal skin growths, cysts are benign (noncancerous) bumps that develop just below the skin. Like lipomas, another common benign skin lump, most cysts are painless, grow slowly, and move easily under gentle pressure.
Unlike lipomas, however, cysts are more vulnerable to infection and inflammation. Two types of cysts that carry a greater risk of becoming infected, swollen, and tender are pilonidal cysts and sebaceous cysts.
Here at Precision Surgery and Advanced Vein Therapy in Glendale, Arizona, board-certified general surgeon Johnny L. Serrano, DO, FACOS evaluates and removes problematic cysts on a routine basis.
Understanding cysts
Cysts are slow-growing, round bumps that develop just beneath the skin. Many cysts appear as white or yellow dome-shaped growths because they’re filled with keratin, an important skin protein that has an oily, cheese-like texture.
Epidermoid cysts, also known as skin cysts, form when epidermal cells aren’t properly shed. Instead, these wayward cells migrate to deeper skin layers, multiply, and form an enclosed sac where they actively secrete keratin. As keratin builds up in the sac, it concentrates into a thick, yellowish paste that expands the cyst and sometimes oozes out.
Cysts that arise from other types of cells — such as pilar cysts, which emerge from wayward hair follicle cells — contain other substances along with keratin. Many cysts are marked by a small, dark “plug” that may ooze pus under pressure. Most cysts are:
- Noninvasive toward nearby tissues
- Symmetrical; round or dome-shaped
- Skin-colored, tan, white, or yellowish
- Tender and pliant (not hard and firm)
- Small, painless, and slow to develop
As the most common cyst types, skin and hair follicle cysts can emerge almost anywhere on your body, but tend to appear on the face, neck, and torso most often.
Pilonidal vs. sebaceous cysts
Most cysts are small, harmless, and discreet, meaning they don’t require medical treatment unless they grow larger, become irritated, or get infected. Some cysts even disappear on their own as time goes on.
Two cyst types that often do require treatment, however, are pilonidal and sebaceous cysts:
Pilonidal cysts
A pilonidal cyst is a round sac of tissue that often emerges at the top cleft of the buttocks, but can develop anywhere along the buttock crease, from the tailbone to the anus. It may be filled with fluid or air, and it’s typically caused by a skin infection stemming from an ingrown hair.
Pilonidal cysts can be a one-time (acute) problem or a chronic condition that returns over time. Whether they’re acute or chronic, however, all pilonidal cysts require treatment.
Although they’re not always painful to begin with, pilonidal cysts often grow larger and more painful without treatment. They can also lead to skin abscesses (swollen pockets of infection) and sinus cavities (empty hollows beneath the skin).
Sebaceous cysts
This type of cyst is often confused for a basic skin cyst. But whereas epidermoid cysts are very common and arise from wayward skin cells, sebaceous cysts are relatively rare and arise from the oil-secreting sebaceous glands that lubricate your skin and hair.
Sebaceous cysts can grow anywhere on the body, apart from the palms of your hands and the soles of your feet. They’re filled with a mixture of lipids called sebum, which is produced by the sebaceous gland. Like the keratin in skin cysts, sebum makes sebaceous cysts appear as white or yellow dome-shaped bumps.
Most sebaceous cysts are painless and harmless, but they may grow larger, break open, or become infected and inflamed. You can monitor this type of cyst for signs of infection or wait and see if it goes away on its own, or you can have it treated. Untreated sebaceous cysts that don’t resolve independently will likely remain with you for life.
Treating problematic cysts
While pilonidal cysts are the only cyst type that always warrants treatment, any type of cyst that’s prominent, irritating, painful, infected, or problematic is a candidate for surgical removal. This includes cysts that are:
- Growing very large or growing rapidly
- More likely to rupture and become infected
- Easily aggravated by clothing or activity
- Conspicuous, unappealing, or hard to conceal
- In a bothersome location (between fingers)
Any cyst that’s infected — sore, red, swollen, or oozing a foul-smelling discharge — requires prompt medical care. Once the infection has cleared, complete surgical removal is the best way to address the problematic growth and prevent recurrence.
Call 623-321-5663 to learn more about the cyst evaluation and removal services available at Precision Surgery and Advanced Vein Therapy in Glendale, Arizona, or use the easy online booking feature to schedule a visit with Dr. Serrano today.