Moles (Nevi) and Melanoma

Moles, medically referred to as nevi, are pigmented lesions that occur on the skin or mucous membranes. They are the result of abnormal development of melanocytes, the cells responsible for skin pigmentation. Moles can appear spontaneously throughout an individual's life, with some present from birth. While most of these pigmented skin lesions are benign, some can degenerate into tumor forms, such as melanoma.

Causes and Risk Factors

Moles, also known as nevi, are common skin lesions formed by the accumulation of melanocytes or nevus cells. These cells are responsible for producing melanin, the pigment that gives skin its color. The process that leads to the formation of moles is not completely understood, but several factors are believed to play a role.

• ‍Genetic Predisposition
  Genetic factors are significant in determining who is likely to develop moles. Individuals with a family history of moles or melanoma are more prone to develop these skin lesions.
• ‍Immune Status
  The body's immune system may influence the development and appearance of moles. A weakened immune system, which can be caused by certain diseases or treatments, might increase the likelihood of mole formation.‍
• Exposure to Ultraviolet (UV) Radiation
  UV radiation from sunlight or artificial sources such as tanning beds can trigger the proliferation of nevus cells. This exposure is a well-documented risk factor for both the development of new moles and the transformation of existing moles.‍
• Pharmacological Treatments
  Certain medications can affect mole development. For example, drugs that alter hormonal levels or affect immune function may lead to changes in mole size or color.‍
• Hormonal Changes
  Hormonal fluctuations during puberty, pregnancy, and menopause can also affect moles. It is common for moles to become darker, larger, or more raised during these periods due to changes in hormone levels.

Melanoma

Melanoma, a malignant skin tumor, is caused by uncontrolled proliferation of melanocytes. In some cases, melanoma develops from a pre-existing mole, while in others, it can develop on healthy skin. Melanoma is particularly aggressive, with the ability to spread both deeply and extensively, reaching lymph nodes and distant organs, leading to metastases relatively quickly.

Early identification and treatment of melanoma can lead to recovery, emphasizing the importance of prevention. This includes controlling risk factors, regular dermatological visits, and surgical removal of suspicious lesions. Regular self-examination of the skin can also help monitor any changes in existing moles and recognize melanoma characteristics.

Types of Moles

Moles can vary widely in shape, size, and color. They can be benign or indicative of skin disorders, making their classification important for dermatological assessment. Moles are primarily classified based on their location and histological features.

Classification Based on Location

• Intradermal Nevi
  These moles occur entirely beneath the epidermis, within the dermal layer of the skin. They typically appear as bright flesh-colored or light brown lesions. Their slightly raised, dome-shaped surface distinguishes them from other types.
• Junctional Nevi
  Located at the dermal-epidermal junction, these moles are generally flat and feature a uniform pigmentation of brown or black. Their placement at the junction influences their flat appearance.
• Compound Nevi
  Exhibiting characteristics of both intradermal and junctional nevi, compound moles are usually raised and possess uniform pigmentation. They arise when nevus cells are found in both the dermis and the epidermis.

Moles can also be classified based on their macro and microscopic characteristics into several types, including Clark's nevus, atypical Clark's nevi, Spitz nevus, Reed's nevus, Miescher's nevus, blue nevus, Sutton's nevus, and Unna's nevus.

Signs and Symptoms

Moles can present with various clinical characteristics. They can be flat or raised, oval or round in shape, with clear or blurred edges. The pigmentation of moles can vary from light brown to blackish, from pink or flesh-colored to red. Some moles can become darker following sun exposure or during pregnancy, while others may slowly lose their pigmentation.

Changes in the appearance of moles, either progressive and rapid changes of a pre-existing mole or the appearance of a new type of lesion, can be the first signs of melanoma.

Risk Assessment

While many pigmented skin lesions remain harmless throughout an individual's life, moles presenting anomalous characteristics should be evaluated by a doctor. Suspicious lesions have irregular, non-symmetrical shapes, with jagged edges or incisions. Changes in color, consistency, and the appearance of signs of inflammation in the surrounding skin can also indicate a malignant evolution.

Diagnosis

Regular dermatological examinations can help evaluate the morphological characteristics of pigmented skin lesions and recognize any suspicious changes. Dermatoscopic examination allows for monitoring of anomalous neoformations and intervention if modifications have occurred. In addition to professional check-ups, periodic self-examination of moles and lesions is crucial.

Treatment

Moles with atypical morphological characteristics can be monitored with periodic dermatological checks or surgically removed. Surgical treatment is generally considered if the mole is deemed abnormal following a thorough dermatological examination, if it is subjected to repeated trauma, or if it causes aesthetic discomfort to the patient.