+ Moles are very common, small (<1 cm), circumscribed, acquired pigmented macules, papules, or nodules composed of melanocytic nevus cells located in the epidermis, dermis, and, rarely, subcutaneous tissue. While moles are benign, the risk of melanoma is related to the number of them present. Melanocytic nevi evolve from the epidermis and involute to the dermis where they gradually disappear.
Moles are asymptomatic and classified as junctional, compound, or dermal melanocytic depending on where they arise and the state of evolution.
Junctional nevi arise at the dermal–epidermal junction, compound melanocytic nevi invade the dermis, and dermal melanocytic nevi are fully involuted into the dermis.
Junctional moles are round or oval macules, or only very slightly raised papules. Compound moles are dome-shaped, sometimes with a cobblestone-like surface, papillomous, or hyperkeratotic. Dermal moles are round or dome-shaped well-defined papules or nodules. Junctional and compound moles are uniform tan, brown, dark brown, or even black with smooth, regular borders, and are discrete and scattered. Dermal moles are skin-colored, tan, or flecked with brown. Moles are never >1 cm in diameter.
Diagnosis is made clinically and the most important thing is to rule out melanoma precursors and melanoma using the ABCDE (asymmetric, uneven borders, color mixed, large diameter, and evolving). The differential includes solar lentigo, flat atypical nevus, lentigo maligna, other raised pigmented lesions, seborrheic keratosis, small superficial spreading melanoma, early nodular melanoma, pigmented basal cell carcinoma, dermatofibroma, Spitz nevus, blue nevus, neurofibroma, trichoepithelioma, dermatofibroma, and sebaceous hyperplasia.
Rule out melanoma precursors and melanoma, and in cases of doubt, use dermoscopy, biopsy, or excision with a narrow margin.
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