Sebaceous cysts are common, benign skin growths that develop when a sebaceous gland or hair follicle becomes clogged or damaged. These slow-growing, painless lumps typically appear just beneath the skin's surface and are most commonly found on the face, neck, upper back and chest, but can occur anywhere on the body except the palms of hand and soles of feet. 

Filled with a soft, cheese-like substance composed of dead skin cells and oils, sebaceous cysts can vary in size from a few millimeters to several centimeters in diameter. While usually harmless, they can become inflamed, infected, or rupture, causing discomfort and potential scarring. Factors contributing to their formation include genetics, hormonal changes, and skin injuries.

Treatment is often unnecessary unless the cyst becomes bothersome or infected. Options range from simple drainage to surgical excision, depending on the cyst's size and location. It's important to avoid attempting to pop or drain these cysts at home, as this can lead to infection and scarring. Professional medical evaluation is recommended for proper diagnosis and treatment.