Blue nevus is a benign change in the skin that does not endanger life and therefore does not need to be removed. However, there are some cases where there is development of malignant cells, but this is only common when the blue nevus is too large or increases in size quickly.
The blue nevus is similar to a wart and develops due to the accumulation, in the same site, of several melanocytes, which are the skin cells responsible for the darker color. As these cells are present in a deeper layer of the skin, their color does not fully appear and therefore they tend to have a blue coloration, which can vary even up to dark grey.
This type of skin change is more frequent in the head, neck, back, hands or feet. It is easily evaluated by the dermatologist, and may affect people of all ages, and is more frequent in children and young adults.
How is the diagnosis of blue nevus done?
The diagnosis of blue nevus is easy. It is performed by the dermatologist only from observation of the characteristics presented by the nevus, such as small size, between 1mm and 5 mm, rounded shape and raised or smooth surface. In case changes in the nevus are verified, it may be necessary to perform a differential diagnosis by biopsy, in which the cellular characteristics of the nevus are observed.
The differential diagnosis of blue nevus is made for melanoma, dermatofibroma, plantar wart and tattoo.
When to go to the doctor
Although the blue nevus is almost always a benign change, it is important to beware of its characteristics, especially when it arises after the age of 30. In this way, it is recommended to go to the doctor when:
- The nevus increases rapidly in size
- Development for shape with irregular edges
- Changes in color or appearance of various colors
- Asymmetric stain
- The nevus begins to itch, hurt or bleed
Thus, whenever the nevus changes after diagnosis it is advisable to consult the dermatologist again for further tests and, if necessary, perform a small surgery to remove the nevus. This surgery can be done in the dermatologist’s office under local anesthesia, and it is not necessary to do any kind of preparation. Typically, the blue nevus is removed in about 20 minutes and then sent to the laboratory to assess the presence of malignant cells.
When malignant cells are found after removing the blue nevus, the doctor evaluates their degree of development and, if elevated, may recommend repetition of the surgery to remove some of the tissue that was around the nevus, so as to remove all cancer cells.