Mucosal melanocytic macules

A mucosal melanocytic macule is a benign, well-defined, oval, brown to black, flat patch, which can be oral, labial or penile in distribution. 

This chapter is set out as follows:

• Mucosal melanocytic macules are more common in women than men 
• The age at onset is approximately 30 years

Distribution

• The lips are the most common site, especially the central third of the lower lip

Morphology

• Lesions present as brown-black macules, and are usually solitary - several lesions should increase the suspicion of a systemic condition such as Peutz-Jeghers syndrome, Addison's disease and multiple lentiginoses (eg the Leopard syndrome)

• Size - under 1 cm in diameter 

• Once developed the lesions usually remain unchanged in size and colour

Dermoscopic examination of oral and genital lesions

• Benign lesions - diffuse pigmentation with a peculiar parallel pattern of partially linear and partially curvilinear light-brown to dark-brown streaks

• Melanoma - the combination of blue, grey, or white colour with structureless zones are the strongest indicators of mucosal melanoma 

• Lesions with no suspicious clinical features, and which do not show signs of ongoing growth, require no treatment

• Features suggestive of melanoma include:
• Asymmetry of shape 
• More than one colour
• Persistent growth
• Dermoscopy - the combination of blue, grey, or white colour with structureless zones

• Patients with suspicious clinical or dermoscopic features should be referred urgently to Secondary Care (two-week wait)