Case Number : Case 2753 - 25 January 2021 Posted By: Richard Logan

I would consider this a dermal nevus.

Yes, It seems a Nevus for me too but I´ve never seen a nevus in that location. 

Dermal naevus?

?Combined blue and dermal common nevus. But the pigmented cells don’t look like dendritic cells. So agree with Colleagues. 

Yes. Looks like an intradermal nevus.

13 hours ago, vincenzo said:

?Combined blue and dermal common nevus. But the pigmented cells don’t look like dendritic cells. So agree with Colleagues. 

Looking more carefully, it seems there are some dendritic cells...???

I think you will see from the clinical picture why we wanted to biopsy this late-onset, atypical pigmented lesion on this elderly man's glans.  if you look closely you can see an area of pigmentation involving the foreskin as well.  Why it has only become clinically obvious at this age is speculative - perhaps the lack of ultraviolet exposure (one would assume!)

This was an example of the very rare phenomenon of  "divided", benign, melanocytic naevus. It is sometimes called a "kissing naevus", a somewhat unfortunate description perhaps!

It's the only time I saw a case during my career.  The phenomenon seems to originate in fetal life.  Melanoblasts migrate to the skin during the second and third months of gestation.  Between the 11th and 14th week, two penile epithelial invaginations occur, one to form the the urethra, the second to separate the glans from the foreskin.  Presumably if a naevus has already been "formed" before this separation, it could be split into two separate foci as here, one on the glans and another on the foreskin. 

There is a more florid example of this phenomenon in the literature: Yung SJ et al, Ann Dermatol 2011, 23: 512.  The same process can occur on adjacent fingers and also the eyelids, with part of the naevus on the upper, and the rest on the lower eyelid.

great case thanks