Naevi

Melanocytic naevi (moles)

A benign collection of melanocytes which are either present at birth (congenital naevi) or acquired, being located at the dermoepidermal junction (junctional naevi) from whence some (compound naevi) or all (intradermal naevi) migrate into the dermis. They arise from the neural crest early in life. If they are arrested in the dermis en route for the epidermis they may be acquired (blue naevi) or congenital (Mongolian blue spot or naevus of Ota). They are often all referred to loosely as moles or birth marks.

Congenital melanocytic naevus / Junctional naevi / Compound naevus / Spitz naevus / Intradermal naevus / Blue naevus / Mongolian blue spot / Naevus of Ota

Congenital melanocytic naevus

Characteristics

Symptoms

a pigmented birth mark of variable size but always larger than acquired moles

Signs

lesion a flat uniform pigmented patch which may be spotted (naevus spilus)
colour brown, may be café au lait in colour
shape oval or round
surface may become thickened and hairy

Distribution

anywhere

Variant

giant bathing trunk naevus

Diagnosis

clinical

Differential diagnosis

see table

Management

Junctional naevi

Characteristics

Symptoms

a flat dark mole

Signs

lesions a macule
colour dark brown and/or brown: often two toned
shape oval or round
surface flat

Distribution

anywhere

Diagnosis

Differential diagnosis

see table

Management

reassurance but excision if in doubt

Compound naevus

Characteristics

Symptoms

a raised brown mole

Signs

lesion a soft papule
colour brown or dark brown, usually two toned
either darker centrally or peripherally
shape round or oval
surface usually smooth but sometimes mamillated
or papillomatous or hairy

Distribution

anywhere

Variants

halo naevus

Diagnosis

Differential diagnosis

see table

Management

Spitz naevus (juvenile melanoma)

Characteristics

Symptoms

a red-brown mole occurring usually in childhood, which grows rapidly initially

Signs

lesion a soft papule occasionally nodule
colour red or reddish brown
shape round
surface smooth

Distribution

anywhere especially face (particularly cheeks) and legs

Diagnosis

Differential diagnosis

see table

Management

often surgical excision

Intradermal naevus

Characteristics

Symptoms

a flesh-coloured mole

Signs

lesion a soft papule which may be pedunculated
colour flesh-coloured
shape round or oval
surface smooth, sometimes hairy

Distribution

anywhere but particularly the face

Diagnosis

Differential diagnosis

see table

Management

Blue naevus

Characteristics

Symptoms

a dark-blue lesion often causing concern as to its nature

Signs

lesion a soft papule or nodule
colour blue or blue black
shape round
surface smooth

Distribution

anywhere but particularly back of hand or foot, and face

Diagnosis

Differential diagnosis

see table

Management

Mongolian blue spot

Characteristics

Symptoms

a large blue-grey blemish usually on the buttocks of a new-born mongoloid or negroid baby

Signs

lesion a large usually single diffuse patch
colour slate blue
shape rounded or oval
surface flat and smooth

Distribution

lumbosacral region

Progression

usually disappears by the age of 7

Diagnosis

clinical

Differential diagnosis

none

Treatment

none

Naevus of Ota

Characteristics

Symptoms

facial birth mark near and in the eye, appearing in childhood

Signs

lesion a large diffuse patch
colour a deep blue on the skin but brown on the conjunctiva
shape diffuse on the cheek patchy or geographical on the conjunctivae
surface flat and smooth

Distribution

face and eye

Diagnosis

clinical

Differential diagnosis

nil

Treatment

lasers may be tried