Clinical Features:

• Peak incidence between 10 and 30 years of age
• Most common on the face, upper trunk and proximal extremities
• Presents as small, raised bluish lesion mimicking blue nevus

Histologic Features:

• Well-circumscribed, symmetric lesion within the dermis, sometimes also displaying a junctional component
• The architecture is that of a wedge-shaped proliferation of tightly packed, pigmented spindle cells
• The spindle cells show a diffuse arrangement in the upper dermis, and become arranged into discreet fascicles as they move into the deep dermis
• The spindle fascicles may have a bulbous contour in the deeper aspects of the lesion, and may extend into the subcutaneous fat.
• The nevus cells are often closely associated with neurovascular and adnexal structures in the deeper dermis.
• Melanophages are often present in association with the nevus cells.
• Focal significant cytologic atypia is often present, and occasional mitoses (1 to 2 per square millimeter) may be seen.

Cases associated with this book:

Deep penetrating nevus
Author: Stephen Lyle, M.D., Ph.D.

Conference: Dermpedia Teaching Collection