If an ovarian cyst is left untreated, it will usually resolve on its own. However, a solid or partially solid cyst may need to be evaluated by a lab to make sure it isn’t cancerous. While most ovarian ...

Also known as a pilonidal cyst, the condition forms when a sac of tissue fills with air or fluid in the crease of your buttocks. Pilonidal cyst, doctors say, is mostly caused by a skin infection.