Pleasanton resident Cindy De Pretis said she "had no respect" for basal cell carcinoma -- the most commonly diagnosed form of skin cancer in the United States -- until a normally minor surgery to remove a cancerous spot on her face more than six years ago unexpectedly morphed into something much more.

She first noticed some blood on the side of her nose "where you'd have a little piercing" while applying makeup on her face in April 2011, but didn't do anything about it until November 2014.

"That's a very embarrassing thing; I pretended this was not a thing," De Pretis told the Weekly. "It would close up and I would think it was healing. It was a long period of time."

Coming from a family with "a lot of basal and squamous cells," De Pretis said she had "been around it and didn't think much about it."

"I had always heard of moles, you're always taught to look out for moles," she said. "No one told me to look out for a little hole. I thought, 'Gosh I've damaged a pore or something like that.' Nearly four years later, it was getting bigger to where I had no more opportunity to ignore it."

A dermatologist's visit confirmed De Pretis had basal cell carcinoma and she was scheduled for Mohs surgery, which involves removing cancerous tissue from the affected site. When she went in for the procedure, De Pretis' doctor told her that "they do about 500 of these a year, but this one surprised me."

Before she left the office, De Pretis was sent to a surgeon but hadn't seen the extent of her surgery yet. "He said, have you seen this, and I'm like, no. He hands me a mirror, and I was in for the shock of my life."

"They ended up removing about half of my nose and a portion of my cheek," De Pretis said. "They said it really kills you and rarely metastasizes but it does eat up and damage. It would have continued eating my skin, the hole would have continued" without surgery.

De Pretis ended up spending nearly two years undergoing additional surgeries, including a forehead flap, followed by many laser treatments.

"It was a really gruesome, gruesome process," she said "I literally couldn't see my grandson. I would have terrified him, he was 1-1/2 to 2 years old. Even today, I wouldn't let him see it. It was bad, I wouldn't go out in public."

For the rest of her life, De Pretis will have facial scars and severed nerves; "it's just the way it is now," she said. "I never thought basal cell would be a big deal. I didn't understand the devastating effects."

According to Dr. Meghan Dickman, a dermatologist at Stanford Health Care-ValleyCare, basal cell carcinoma rarely spreads to other areas or metastasizes but can have significant consequences, if left untreated.

Most often presented as a small non-healing wound, basal cell carcinoma doesn't come from moles, according to Dickman. "They often can go under the radar. It's not that classic photo you see of a black, growing lesion," Dickman said. "They can sometimes be so subtle, just a shiny pink bump -- it can really be quite subtle."

It's been "a very common scenario" where a patient would see Dickman for what they had mistaken as a pimple on their face but was actually basal carcinoma.

"It often is just a small pink bump," Dickman said. "I always tell patients, if you notice a non-healing wound, that's a reason to see a dermatologist. Because that's a very common presentation for basal cell, but other skin cancers can do the same."

The biggest risk factor for basal cell carcinoma is a history of blistering sunburns. "It is high-intensity, intermittent sun exposure, except in rare situations like genetically inherited syndromes," Dickman said.

"Squamous cell (carcinoma), in contrast, the biggest risk factor is chronic everyday exposure," Dickman added. People in outdoor professions including police officers, agricultural workers and construction laborers have greater odds of developing squamous cell carcinoma.

Squamous cell has a higher risk than basal cell carcinoma because of the possibility that it could spread to other areas such as lymph nodes. "Squamous cells typically are more of a crusted pink bump," Dickman said. "Sometimes people will think it looks a bit like a wart. It can be rough and almost like sandpaper."

Any kind of skin cancer is worrisome but Dickman said, "Melanoma is definitely the skin cancer we worry about the most because it can be lethal."

When caught early, however, melanoma is "extremely treatable." Sun exposure increases the risk of melanoma, but having a family member with it can increase one's risk as well.

"Melanoma is tricky because it doesn't always happen in sun-exposed areas," Dickman said. "I've seen it on patients' feet, genitals, inside the mouth or in the eye. It's not just those areas where you think about getting a lot of sun exposure."

Melanoma will usually show up as a dark or changing lesion on the body, and can pop up in an existing mole that seems to be darkening or growing.

"Some things I find helpful for patients to look for is something growing rapidly," Dickman added. "Anything itchy, painful or that seems to be bleeding, those can be things to look for."

For the best sun protection, Dickman recommends applying sunblock daily, and tells patients that "it should meet two criteria -- broad-spectrum and SPF 30 or higher."

"The price, brand and ingredients are less important, but if you are concerned about environmental effects of sunscreen or absorption into the bloodstream, then zinc oxide or titanium dioxide are good," Dickman said.

However, because "in the best of situations, sunscreen only lasts two hours," Dickman said people should be sure to reapply it regularly. Wearing photo-protective clothing while outdoors is also a good idea, and is now widely available

Though people with fair skin are more likely to get sunburned, Dickman said everyone should take the same precautions: "You may be less likely to sunburn, the more pigment you have, but I certainly see skin cancer in all types of people."

"(Skin cancer) tends to be caught later because it might not be on the top of their radar but it does happen," Dickman said. "All people should employ self-protecting measures, no matter what their skin type."

Dickman also recommended annual skin checks for anyone over the age of 50, and anyone with a history of skin cancer.

After learning these lessons the hard way, De Pretis said she has taken them to heart: "I stay out of the sun, I've got my special sunscreen on, and since then I've had quite a few basal cells but I get skin checks every six months."

"Anything that looks suspicious, it's better to go get it checked out right away," De Pretis said. "I probably could have saved myself a forehead flap if I had just gone in 2011."