Case Number : Case 2071 - 15 May 2018 Posted By: Uma Sundram

Age of the patient and big hyperchromatic nuclei of melanocytes make me think of melanoma

Pigmented epithelioid melanocytoma.

What about a partially regressed dermal nevus?  

It's really a maze - pigmented epithelioid melanocytoma, animal type melanoma, Epithelioid blue nevus, pigment producing melanoma etc etc... Waiting for enlightenment from the experts. 

Considering the age I would be worried about partially regressed melanoma. Would add a note in the report and talk with the dermatologist

My apologies for the late comment. I spent most of Monday in a plane to London but am here now for the London Dermatopathology Symposium. A welcome to all those who are here, and a plug for the LDS for those who've never been - it's a very relaxed way to learn about dermatopathology from the experts with tons of new material and review of old material. Good times!

Regarding the posted case, a difficult one indeed. It's a regressing lesion; difficult to say if it's a regressing melanoma or a regressing nevus. I favored nevus because the remaining cells appear relatively bland, with mild cytologic atypia. Nevertheless, given the age of the patient, I recommended excision of any remaining lesion. While PEM and animal type melanoma are good thoughts, those tend to have larger, more epithelioid cells, whereas here, the cells really seem 'nevoid'.