Skin Mole or Nevus

Melanoma skin cancer ---> Pre skin cancer ---> skin cancer moles

Lentigo
A lentigo is a common lesion that presents as a small, pigmented macule due to an increase in the number of melanocytes within the basal layer of the epidermis. These are unaffected by sunlight. Solar lentigines develop on sun-exposed sites following either acute severe sunburn in young adults or chronic ultraviolet exposure in the elderly. Multiple lentigines may rarely be a manifestation of Peutz-Jeghers syndrome, particularly when distributed on the lips, buccal mucosa and acral sites.

Acquired melanocytic nevi
Acquired melanocytic nevi are common benign proliferations of melanocytes. They can be classified according to the site of the cluster of melanocytes. Junctional nevi describe the position of the cells at the dermal-epidermal junction above the basement membrane. Intradermal nevi describe cells that are exclusively in the dermis. Compound nevi have histological features of both junctional and intradermal nevi.
Junctional nevi present as small, dark brown, evenly pigmented, symmetrical macules. The majority of naevi in children are junctional and occur on any body site. Compound nevi (where melanocytes are present in both the epidermis and dermis) occur at any site and vary from light brown papules to dark brown papillomatous plaques. Intradermal nevi are usually detected in the third decade, frequently on the face, and may be devoid of pigment. They may be dome-shaped or pedunculated skin tags. These lesions appear in early childhood and reach a maximum in young adulthood. There is then a gradual involution, and most lesions disappear by the age of 60. A skin biopsy is only required when clinical differentiation from malignant melanoma is difficult.

Blue nevus
A blue nevus is an acquired, benign, firm, dark blue to black, sharply defined papule representing a deep dermal aggregate of melanocytes. The dermal melanocytes are thought to represent melanocytes which have failed to migrate from the neural crest to the epidermis during fetal life. Blue nevus is most common on the dorsum of hands or feet of older children and young adults. Malignant change is very rare.

Spitz nevus
A Spitz nevus is a benign melanocytic tumor that is distinct from acquired melanocytic nevi on both clinical and pathological grounds. The majority occur in children as a discrete, red-brown or pink papule on the face. The clinical presentation is distinctive and there is often a history of recent rapid growth. Differentiation from malignant melanoma may be difficult and in these cases complete excision is recommended.

Mongolian spot
A Mongolian spot is a congenital grey-blue macular lesion that can occur anywhere on the skin but is characteristically located on the lumbo-sacral area. Histologically there are ectopic melanocytes in the dermis, possibly interrupted in their migration from the neural crest to the epidermis. Mongolian spots disappear in early childhood. No melanomas have been reported in these lesions.

Nevus spilus
A nevus spilus is a common lesion consisting of a light brown macule, varying in size from a few centimeters to a very large area, with many darker small macules (2-3 mm) or papules scattered throughout. Histologically, the background macule shows an increased number of melanocytes and the scattered lesions are either junctional or compound nevi. Malignant melanoma very rarely arises in these lesions.

Dysplastic melanocytic nevus
Dysplastic melanocytic nevi are melanocytic lesions with atypical clinical and histological features. They are regarded as potential precursors of superficial spreading melanoma and also as markers of persons at risk for developing primary malignant melanoma. These pigmented lesions are clinically distinct from acquired melanocytic nevi, being larger and more variegated in color, with an asymmetrical outline and irregular border. Lesions may occur sporadically or may arise against a background of dysplastic nevus syndrome, an autosomal dominant condition with multiple atypical nevi. Surgical excision of lesions with minimal margins is recommended, especially in lesions that are changing or those that cannot be closely followed by the patient (on the scalp or back).

CLINICAL ALERT
Six signs of malignant melanoma
A
Asymmetry in shape
B
Border is irregular
C
Color variation-shades of brown, black, grey, red and white
D
Diameter is usually large, >6 mm
E
Elevation is almost always present