Case Number : Case 2716 - 03 December 2020 Posted By: Saleem Taibjee

This is a lovely example of pseudomelanoma.  There is a dermal scar from previous naevus surgery and also foci of foreign body reaction, possibly to suture material.  The lower part of the naevus is still present below the scar, and atypical melanocytic proliferation in the epidermis above it.  A good reason for leaving benign naevi alone!

Agree with Dr Logan.

Benign Nevus with Pseudomelanomatous Features. 

There are two melanocytic lesions in the same specimen 

1): Favor "Recurrent nevus” over “scar/traumatized nevus”, because of body foreign granuloma, probably versus suture material. 

2): Question: is that a residual shoulder of previous nevus? Or is that another separate nevus from the previous one by the two nrormal skin specimens in fig 3?

I think the last not cicatricial appearing nevus is the residual adjacent half nevus. 

Nice recurrent nevus. Shows all its typical characteristics

Hi. Yes this is a nice recent example of recurrent naevus, with probably the most impressive pseudomelanoma phenomenon I have personally seen, including prominent upward spread. Amongst the diagnostic clues is the horizontal demarcation of the atypical junctional component to the area of underlying scarring. The dermoscopy is also quite interesting.

At the time of surgery, the patient provided no relevant history. However, when I telephoned her with the histology result, she then recalled scraping off the top of the mole on a wooden beam in the attic a few years previously!

Very interesting case. So the foreign material was probably a wood splinter...

What do others think about this entity being called "recurrent naevus"?  This name implies that the naevus was removed and then regrew.  In fact, of course, this situation arises when only the top of a naevus (almost always pigmented) is removed, either surgically, by inappropriate cryotherapy or by accident as in this case.  More accurately it is a persistent naevus due to incomplete removal.  That portion beneath the scar is part of the original naevus.  The atypical melanocytic proliferation above the scar is not really naevus at all, but it is the part which causes all the concern because of its typical pigmentary pattern.

I prefer the designation of pseudomelanoma.

Traumatized nevus

I use recurrent/persistent nevus. very nice example.