Case Number : CT0052 Adam_Bates

Ancient melanocytic nevus.
 

There are some histologic criteria that make me think of Wiesner nevus - another one by dr. Diwan ?!?!  Theese criteria are: intradermal nevus with no obvious maturation, presence of epithelioid cells with nuclear pleomorphism, inflammatory infiltrate. Of course, it needs confirmatory BAP1 status. This could be also an ancient nevus, but I would not argue much with someone calling this an intradermal Spitz.

Intradermal Spitzoid melanocytic tumor of unknown malignant potential (in absence of stains/studies).

There is a hint of maturation with asymmetric melanin pigment in one asymmetric superficial dermal focus (3rd photo). The remainder of the tumor shows markedly pleomorphic epithelioid nuclei with prominent, predominantly solitary violet nucleoli, and random multinucleation, vs. smudgy senescent-type hyperchromatic round to spindled nuclei. I can't see any mitotic activity or junctional component. There is an asymmetrical chronic inflammatory response with significant plasma cell component.

I think this likely a benign Spitz nevus. However, the age range is getting high (26 yo) if a new / changing lesion. The overall asymmetry of architecture and cytology, with significant plasma cell component, are of concern and would prompt me to evaluate (1) Ki67 or other proliferative index marker, and (2) loss of P16 nuclear/cytoplasmic immunostaining (vs. FISH/CGH) to ensure this is not a wolf in sheep's clothing.

Intradermal naevus with "degenerative" nuclear atypia