Learning Objective
By the end of this module, the learner will be able to recognize, classify, and describe the key clinical and microscopic features of common benign melanocytic lesions, including freckles, lentigines, nevi, and dysplastic nevi.
Benign Melanocytic Lesions
Ephelides (Freckles)
- Light-brown macules in sun-exposed areas.
- Microscopy: ↑ melanin in basal layer; melanocyte number normal.
Solar Lentigines (Actinic Lentigines)
- Hyperpigmented macules in adults on sun-exposed skin.
- Microscopy: Elongated rete ridges; discontinuous increase in melanocytes.
Congenital Nevi (Birthmarks)
- Present at birth.
- Giant congenital nevi carry an increased melanoma risk.
Melanocytic Nevus (Mole)
- Benign melanocytic tumor related to sun exposure.
- Types: Junctional, Compound, Intradermal.
- Uniform tan/brown color, sharp borders, stable over time.
- Malignant transformation is rare.
Dysplastic Nevus
- Term used by pathologists for nevi showing architectural disorder and cytologic atypia.
- Clinical significance lies in the increased melanoma risk when numerous.
