Though six millimeters is the measurement that often comes up in the “signs to look for” lists for melanoma, it can be the size of a pinpoint. The picture above shows a four millimeter tumor.

“Melanoma can come in all sizes,” says Dr. Tess Mauricio, MD, FAAD, a leading board certified dermatologist from Stanford University Medical School and CEO of

“I have seen melanoma that is as small as two to three millimeters,” says Dr. Mauricio.

Smaller than Two Millimeters

A case was reported in the journal Dermatology Practical & Conceptual (2013) of a 1.6 mm melanoma on a woman’s arm.

This tiny melanoma was discovered during one of her screening exams, as she had over a hundred moles.

“A proportion of melanomas have been found not to fit the D criterion of the ABCD acronym,” states the DP&C paper, “where D stands for a diameter of 6 mm or greater.”

The paper adds: “Such small melanomas have a reported frequency of 11.4–38.2% of all melanomas.”

In a 2014 Case Reports in Oncological Medicine report, melanomas equal to or less than two millimeters are referred to as micromelanomas.

The well-publicized ABCD checklist for screening has led some laypeople to believe that it’s impossible or nearly impossible for a melanoma to ever be smaller than six millimeters.

But the ABCD’s are a guideline.

Due to the documentation of plenty of melanomas under six millimeters, a fifth checkpoint has been added: “E” for evolving, so that the updated guidelines are now ABCDE.

“This paper reiterates the fact that when it comes to a melanoma, size does not matter,” says the CROM review.

“Micromelanomas, melanomas under 2 mm, are being increasingly reported and given the minute size, the ABCD screening acronym becomes redundant,” says the paper.

Many Melanomas Are Smaller

than Six Millimeters

More melanomas are four to five millimeters than under two millimeters, but yes, they can be much smaller.

However, they’re more likely to be discovered when they are larger, simply because they are more easily seen as they grow.

Tiny melanomas on the arm or face will be more easily spotted by the patient during self-exams or even incidentally, than will be same-size tumors located on the back of the legs or the back.

A coworker of mine once showed me his newly diagnosed reddish melanomas on his arm. One appeared to be two millimeters while the other appeared to be one mm.

Don’t assume that a new “mole” is too small to be a melanoma. A tumor that does not arise from a pre-existing mole needs to start from somewhere.