Pilonidal cyst on the buttocks of a 40 year old male patient. This common cyst is located in the crease of the buttocks and is usually caused by a skin infection. It is more common among adult men under 40 years old and those with thick body hair. Pilonidal cysts can appear once or they may be recurring. If they?™re not treated, they can also lead to painful abscesses. Treatment will depend on the nature of the cyst, however draining the cyst, antibiotics and surgery are among the methods.