Sean Klepper M.D.
Artur Zembowicz M.D....
Also known as: inverted type A nevus
- 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
- 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.