Also known as: clonal nevus

Clinical Features:

• This refers to discrete nests of nevus cells within the dermal component of an ordinary nevus.
• Often not recognized clinically, unless a change--such as a change in color--occurs in a common or congenital nevus

Histologic Features:

• Typically well-circumscribed nests of nevus cells within the upper dermis of a common or less often congenital nevus
• The clonal nests stand out as being morphologically quite different from the background nevus cells: the clonal cells are usually epithelioid, with abundant pigmented cytoplasm and irregular nuclei with small nucleoli.  In contrast, the background nevus cells are typically of the type B ("lymphocyte like") variety.
• Melanophages are usually abundant in the adjacent dermis.
• Mitoses are absent or very rare.