Case Number : Case 1983 - 10 Jan 2018 Posted By: Iskander H. Chaudhry

Superficial atypical Spitz tumor vs spitzoid melanoma arising within superficial atypical Spitz tumor

No maturation. Expansive growth of the dermal nests...this is a melanoma!

I would stain it (HMB45 and Ki67) and FISH it. 

My guess is there would be not a lot of agreement unless doing what Dr. Diwan suggested. But I would not really feel comfortable calling it benign. 

Difficult! Atypical compound Spitz tumour of low risk. Agree that FISH, CGH etc. may be helpful but I would not call this melanoma without additional criteria (that I don't see here) including asymmetry, pagetoid spread laterally, significant dermal mitotic activity at all levels and lack of different clones. It looks out. Watchful waiting only for me.

Favour melanoma here

I'm concerned about melanoma too, but am not willing to pull the trigger yet. I am not a big 'stain' or special studies person... So if it's not out, probably ask for a re excision and watch over time. 

Hi Everybody,

Doctor Chaudhry's final diagnosis was STUMP, a Spitzoid Tumour of unknown malignant potential, the main reason for this was, despite the nuclear pleomorphism, mitotic activity was virtually absent.

Nice and difficult case!