When multiple moles (nevi) appear on a person's skin, they usually look similar to each other.
However, sometimes a mole may appear that is different from all the others. Such a mole is called an "ugly duckling".
It may be larger or smaller, darker or lighter, or it may be a single mole that changes over time. Dermatologists and oncologists use the ABCDE system to differentiate common moles from melanoma.
Oncologist of the 1st category of the HappyDerm medical center Lyudmila Artyushkevich explained what these letters mean.
- A (asymmetry) – asymmetry. Moles of irregular shape cause concern.
- B (borderirregularity) – uneven border. Melanoma often has unclear outlines.
- C (color variegation) – variegation of colors. Several colors in a mole indicate melanoma.
- D (diameter) – diameter. An ideal mole is up to 6 mm in size.
- E (evolving) – development. Itching, bleeding, rapid increase in size and change in shape or color of a mole are of concern.
However, the sensitivity and specificity of the ABCDE system for early melanoma is less than 50%.
Oncologists use the F-value (funny, strange), also known as the ugly duckling sign, to identify a mole on the skin that stands out from the crowd.
This symptom may be the only early sign of skin melanoma.
If a mole appears that has an appearance different from others, it is considered suspicious and should be shown to a doctor. None of the listed signs of melanoma are decisive. The doctor always analyzes all the signs (age of the patient, duration of the mole, changes in its dynamics and appearance).
To improve the accuracy of diagnosis, the dermatoscopy method is used, which allows examining the mole at high magnification and studying its structure in detail. The final diagnosis is established after removing the formation and conducting a histological examination based on the data obtained.
The assessment of the "ugly duckling" symptom is not a diagnostic sign of melanoma and does not provide specific information about its presence. However, this rule may serve as a reason to contact a doctor for a professional examination and diagnosis.
The dermato-oncologist conducts a visual examination of skin lesions, comparing them with each other, and pays special attention to abnormal lesions.
