Dr. Pimple Popper treated twin sisters, and their golf ball-sized cysts exploded pus onto her office walls

• Dr. Pimple Popper treated twin sisters Stacie and Tracie who had pilar cysts on their scalps.
• Each sister has three cysts, and they exploded when Dr. Pimple Popper cut them open.
• Stacie's cysts were harder to remove because they'd popped and oozed previously, creating scar tissue.

Dr. Pimple Popper usually sees one patient at a time, but on tonight's episode of her show "Dr. Pimple Popper," the celebrity dermatologist treated fraternal twins with the same skin condition.

Tracie and Stacie from National City, California, came to Dr. Sandra Lee's office after they both developed multiple golf ball-sized lumps on their scalps. They said they noticed their first bumps develop around 15 years ago, and they've been occurring ever since.

"I just want a normal life, to go out in public and not have people stare at me," Stacie said.

Read more: Dr. Pimple Popper cut into a woman's forehead 'nipple' to remove a lipoma that looked like a shrimp

After their daughters urged them to get the lumps checked out for health reasons, Tracie and Stacie decided to see Dr. Pimple Popper together.

"I want our family to stop worrying about us," Tracie said.

Dr. Pimple Popper identified their growths as pilar cysts.

Pilar cysts are the most common type of cyst, and usually develop on the scalp. According to the National Institutes of Health, less than 10% of the population gets pilar cysts and they typically aren't cancerous. Pilar cysts fill with keratin, a protein found in skin cells, which looks thick and white liquid when extracted from under the skin.

Lee said these growths aren't genetic, which explains why the sisters were the first in their family to experience pilar cysts. At the same time, their similar genetics could mean they have similar skin types, which could explain why they both developed the skin condition, according to Lee.

Tracie had her pilar cysts removed first

Stacie volunteered her sister Tracie to go first.

To start the procedure, Dr. Pimple Popper injected each of her three cysts with a numbing solution. She wasted no time cutting through the center of the largest cyst behind Tracie's ear, which immediately spurted out a grayish-white liquid that Stacie said looked like mustard.

Read more: Watch Dr. Pimple Popper cut pebble-sized nodules off a man's nose and pop his inflamed eyebrow cyst

Lee was able to remove the remainder, then moved on to the second one which had a more oatmeal-like texture, but exploded similarly to the first.

That's why Tracie said, "Brace yourself for impact!" when Dr. Pimple Popper started to treat her final growth. After even more spurting, Lee was able to successfully remove the cyst and stitch all three up.

Then it was Stacie's turn

Stacie went next, and her cysts were more complicated to remove.

That's because some of them had opened and oozed over the years. When the cysts healed after opening up, they formed scar tissue that was stuck to the inside of her skin.

"Hers is a little more like putty," Lee said of Stacie's growths.

After numbing Stacie's three cysts, Lee was able to quickly remove one at the center of her scalp. It left a gaping hole, which Lee stitched up.

The other two proved more difficult because of their thick texture, but Dr. Pimple Popper persevered, using her fingers to squeeze out the yellow and brown insides.

The last cyst even gave a show, squirting so powerfully that it hit Lee's office walls. Like with Tracie, Lee stitched up Stacie's cysts and sent her on her way.

"Sisters that spray together, stay together," Tracie said.