Case Number : Case 1453- 19 January Posted By: Guest

Junctional melanocytic nevus of special site (umbilicus)

Agree with Raul. Junctional melanocytic proliferation with 'site related atypia'. Was this an excision or incisional biopsy?

Dr. Hurt just for the purpose of learning, in your experience what is the usefulness of melanocytic markers in this kind of lesions? do you use to have a better assesment of melanocytic population (architecture)? Thanks in advance.

Fibroplasia, no ascent cells, little epidermal infiltration of melanocytes push toward diagnosis of junctional nevus; but the irregular nesting pattern of atypical cells (more in fig4), although small nests, looks like expansive. Difficult case. I agree with Melan-A.

Mildly dysplastic, at most.

It was clinically atypical and yet not excised. Is this normal practice? Certainly risky. I have been trying to advise our clinical colleagues for years either leave it alone (if you are not worried) or if you are at all worried then excise with a clear margin of at least 2 to 3mm of normal skin (beyond any faint halo of pigmentation) if you want a confident histopathological opinion (this is more true than ever for small, recently grown, often impossible to classify lesions). Having said all that I favour a mildly atypical junctional melanocytic proliferation with no overtly worrying features, commensurate with the anatomic location, but "if there is any clinical concern complete excision with clear margins would be recommended".

I think these types of cases are so challenging! This was an attempted excision but the lesional cells did extend to the margins. We did Melan A and saw that the cells did not show full thickness upward scatter although as you can see from the H+E stained sections, there is multifocal limited scatter of melanocytes. I shared this with my group and we were in agreement that there is atypia, probably commensurate with the site (umbilicus). Recommended either close clinical follow up (if the patient was comfortable with this) or a narrow re excision to ensure that the lesion was completely removed. Over the years I have often done just Melan A on cases like this. This is a clean and relatively unambiguous stain. It allows one to see the expanse and architecture of the lesion and better assess lateral circumscription. As you can see, in H+E stained sections relatively small melanocytes often blend in with keratinocytes, making assessment difficult.