Diagnosis:

Dysplastic naevus

Comments:

DYSPLASTIC NAEVUS:

•         Somewhat irregular pigmented macule, or pigment papule with macular periphery
•         Sizes vary; largest examples may exceed 1 cm in diameter
•         Junctional or compound melanocytic naevus
•         Richly cellular junctional component
•         Junctional nests irregularly spaced and shaped
•         Rete ridges irregularly elongated and oriented, with bridging
•         Subepidermal lamellar sclerosis ('lamellar fibroplasia')
•         Nuclear pleomorphism and anisochromasia ('random atypia') of junctional component
•         Dermal component usually small cell type, with pigmentation in all levels
•         Dermal melanophages and perivascular lymphocytic infiltrates

Presence of many such dysplastic naevi, esepcially in association with history of melanoma, or family history of melanoma, indicates substantial melanoma risk and necessitates close follow-up. Most examples are, however, isolated lesions not associated with melanoma history. Melanoma risk appears to be slightly higher than in other individuals, but the difference is small and has no concrete consequence (apart from advice to avoid excessive UV exposure).