Blue Nevus (also known as the blue nevus of Jadassohn–Tièche, blue neuronevus, or dermal melanocytoma) is a benign skin growth that is primarily characterized by its distinct blue to dark blue coloration. This type of nevus typically appears during puberty, although it can manifest at any age, even at birth. Multiple blue nevi in one individual are rare. Statistically, blue nevi tend to occur more frequently in women compared to men.
The exact cause of blue nevi remains unclear. However, several factors have been identified that may predispose individuals to develop these neoplasms. These factors may influence the likelihood of their appearance or growth:
The diagnosis of blue nevi typically involves a clinical examination, which includes a thorough visual inspection of the skin formation as well as dermatoscopy. If there are concerns about the possibility of malignant transformation, a biopsy may be performed for further analysis.
Visually, a blue nevus appears as a small spot or a slightly elevated nodule on the skin. It is typically symmetrical, with shapes ranging from oval or round to spindle-like. The surface texture of the nevus is usually similar to that of the surrounding skin, which may be smooth or even glossy, especially in smaller nevi. In larger nevi, over 10 mm in diameter, the surface may appear slightly more textured or tuberous.
The edges of the blue nevus are generally blurred or ill-defined, although they are usually smooth. In some cases, large blue nevi may have uneven or jagged edges, which could be an indication of potential malignancy. The color of the nevus ranges from blue to dark blue, with shades of gray-blue or blue-brown occasionally visible, reflecting the depth at which the pigment is deposited in the dermis. The intensity of the color tends to fade from the center towards the periphery, and in larger nevi, color heterogeneity or spotting may be present, resulting in a polychromatic appearance.
Hair is typically absent in blue nevi, although in some cases, coarse, dark hair may grow around the edges of larger nevi, particularly in congenital forms.
Blue nevi generally do not exceed 10 mm in size, and their growth is typically slow. Nevi larger than 1 cm are quite rare and are referred to as “blue cell nevi.” On palpation, these nevi feel similar to normal skin but may be slightly firmer, especially when they protrude above the skin’s surface. There are no subjective symptoms or sensations associated with these nevi.
These neoplasms are most commonly found on the trunk, limbs, or neck. It is quite rare for them to appear on the head. For large blue cell nevi, the sacro-gluteal region is the most typical area of occurrence.
Upon dermatoscopic examination, the following features are commonly observed in a blue nevus:
For acral (palm and sole) blue nevi, there are additional dermatoscopic features:
Blue nevi need to be distinguished from several other pigmented neoplasms, including:
In most cases, blue nevi are considered to be benign and pose no immediate risk. However, compared to common pigmented nevi, blue nevi do carry a slightly higher risk of transforming into melanoma. The risk for melanoma in blue nevi is less than 1%, while for simple pigmented nevi, the risk is typically around 3%. Signs that may indicate potential malignancy include changes in the appearance of the nevus or the development of new sensations such as itching or pain.
Although the risk of melanoma is slightly elevated in blue nevi, the presence of this risk is generally more significant in larger blue nevi, particularly those that exceed 20 cm in diameter. The risk of melanoma in blue nevi under 20 cm remains low, typically less than 1%.
Multiple or large congenital blue nevi may also be associated with certain genetic conditions or syndromes, making it essential for these individuals to receive thorough and ongoing medical evaluation.
For blue nevi that show no signs of damage, changes in appearance, or new sensations, self-monitoring is typically sufficient. This should include periodic checks at least once a year, with assistance from others for areas that are difficult to inspect directly. If the nevus experiences mechanical damage, excessive exposure to ultraviolet or ionizing radiation, or noticeable changes in size or sensation, it is essential to seek medical attention from a dermatologist or oncologist.
A healthcare provider will assess whether continuous monitoring is required or if the nevus should be surgically removed. Nevi that are subjected to repeated physical trauma from clothing, jewelry, or occupational activities should be considered for removal.
Photographic documentation of the nevus can provide valuable records, allowing for the detection of even minor changes over time. For individuals with multiple blue nevi, it is highly recommended to create a map of their skin neoplasms, which will simplify future observations and the identification of any new or altered formations.
Patients with blue nevi should consult a dermatologist or oncologist at least twice a year (typically before and after the summer months) to assess any changes in the nevi’s appearance. Regular mapping of skin neoplasms can aid in tracking any developments or changes in existing lesions.
The recommended treatment for blue nevi is surgical excision, typically using classic, electric, or radio scalpels. After removal, a histological examination is required to confirm the benign nature of the lesion.
Destructive treatments such as laser removal or cryotherapy are not advised for blue nevi due to potential risks and complications.
The prevention of nevi formation and their potential for malignant transformation involves careful and considerate skin care:
It is crucial to have regular exams of blue nevi, seek timely consultation with a specialist if any changes occur, and remove potentially harmful neoplasms as soon as possible to maintain skin health and prevent complications.
