SAN DIEGO -- Melanoma is the deadliest form of skin cancer, and could be hidden from your view.

The last place where you might look for melanoma is exactly the place it could show up, like between fingers and toes, on the scalp or in the mouth.

Some areas not hidden from view can even fool doctors.

Bonnie Johnson knows just about every freckle, mole and sun spot on her body. She has had six melanoma skin cancer cases.

Johnson said, "Five of them looked like moles, discolored and changed a little bit."

The sixth one did not look like melanoma at all, she said.

"That was right on my right clavicle. I didn't even notice that one,” added Johnson.

Dermatologist Dr. Nancy Satur said, “Bonnie's melanoma was so subtle none of you in this room would look at it and be concerned about it all. It was a very subtle pink mark that was raised.”

Most melanomas follow the alphabet:

Asymmetry: One half of the mole is different from another.

Border: The edge or border is usually ragged, notched or blurred.

Color: A variety of colors appear with the same mole.

Diameter: It is generally bigger than an eraser on a pencil.

"You could have a melanoma that passes all those tests and still be a melanoma. That's the scary thing," said Johnson.

Satur said most melanomas are typically dark in color and follow the ABCD’s. However, she is finding some that masquerade as innocent looking, lighter-colored moles or lesions.

Satur said, "A spot on her clavicle was pink, smaller than a pencil eraser. It was not raised, very subtle and I would say shiny."

Satur performed a skin exam on Johnson and the test discovered what could be another hidden melanoma.

The mole was removed and sent off to pathologists for testing.

Because of diligent checking, all of Johnson’s melanomas have been caught early.

"I come every three months because we have caught them all before they got into my skin layers and spread into their lymph system," said Johnson.

Johnson does not take chances and advised others not to take chances either.

If you notice something not quite right on your skin, Johnson suggested, “Go with your gut instinct and get it checked.”

A small percentage of melanomas can develop in places that are not easily detected, such as under nails, palms of the hands and soles of the feet.