A nevus, commonly known as a mole, is a benign skin growth formed by a cluster of melanocytes, cells responsible for producing skin pigment. These growths can appear at birth or develop later in life. While moles can cause concern due to some characteristics overlapping with melanoma, a type of skin cancer, compound melanocytic nevi are typically non-cancerous and a common form.
Understanding Compound Melanocytic Nevi
Compound melanocytic nevi are characterized by melanocytes in both the epidermis (superficial layer) and dermis (deeper layer). This dual location of nevus cells contributes to their unique appearance. They often present as raised, dome-shaped lesions, ranging from skin-colored to tan or brown. Some exhibit a “fried egg” appearance, with a darker, raised central area surrounded by a lighter, flatter periphery.
These common moles frequently develop during childhood or adolescence. They are generally small (2 to 7 millimeters) and may have hair growing from them. Their pigmentation is usually evenly distributed, and they typically have smooth, regular borders. Compound melanocytic nevi are considered benign.
Signs of Concern
Distinguishing a benign mole from a potentially cancerous one like melanoma is important. The “ABCDEs” of melanoma serve as a helpful guide for self-examination:
Asymmetry: One half of the mole does not match the other in shape or size.
Border: Irregular, scalloped, or poorly defined edges.
Color: Varying shades, such as different tones of tan, brown, black, or areas of white, red, or blue.
Diameter: Typically larger than 6 millimeters, though they can be smaller.
Evolving: Any changes in the mole’s size, shape, color, or new symptoms like itching or bleeding.
These guidelines indicate when professional medical advice is warranted, but are not definitive diagnoses.
Professional Evaluation and Diagnosis
When a healthcare professional, typically a dermatologist, evaluates a suspicious mole, the process begins with a visual examination. They may use a dermatoscope, a specialized magnifying tool that allows for a detailed view of the skin’s structure and pigmentation patterns. This non-invasive tool helps differentiate between benign and suspicious lesions. If the mole remains suspicious after dermoscopy, a biopsy is performed.
A biopsy involves removing a tissue sample from the mole for microscopic examination. Common types include shave biopsies (removing top layers), punch biopsies (extracting a deeper, cylindrical sample), and excisional biopsies (removing the entire mole with a margin of surrounding skin for higher suspicion). The removed tissue is then sent to a pathologist for histopathology, which provides a definitive diagnosis as either a benign nevus or melanoma.
What Happens Next
If the pathology report confirms the compound melanocytic nevus is benign and completely removed with clear margins, no further treatment is typically required. Patients should continue regular self-skin checks and annual professional skin examinations with a dermatologist. Sun protection measures, including sunscreen use and protective clothing, are encouraged to reduce the risk of new moles or skin cancers.
Should the biopsy reveal melanoma, further medical intervention is necessary. Treatment often involves wider surgical excision, with the extent depending on the melanoma’s thickness and location. Depending on the stage and spread, additional therapies like sentinel lymph node biopsy, immunotherapy, targeted therapy, chemotherapy, or radiation may be considered. Early detection of melanoma significantly improves treatment outcomes.