Case Number : Case 2045 - 09 April 2018 Posted By: Iskander H. Chaudhry

Good symmetry from left to right and good circumscription at the bottom. Nests of epithelioid cells with pigment retained in the dermis. No atypia. I think this is a combination of epithelioid blue nevus and Spitz nevus- a blitz nevus

Difficult. Agree with left half. But the right half of the lesion is expansive in  dermis, with deep mitosis and cellular atypia. Atypical Spitz Nevus? Spitzoid Melanoma?  I don’t know. 

Please Dr Iskander what’s the 2034’s diagnosis?

Agree with Vincenzo. The right-half is different in growth pattern the the left which makes the lesion asymmetric. Deep mitoses and epidermal consumption are worrisome findings. Comparative Genomic Hybridization may be helpful. 

Me too, I do not like the right half, melanoma arising in a nevus? 

Vincenzo - 2034 Diagnosis now posted! Please find link below. : )

Disturbing! Not sure it's Spitz group. Suggest initial panel of IHC, p16, Ki67, HMB45, MelanA +/- BRAF IHC. If BRAF+ it's NOT a Spitz and then abnormality of p16 might swing it to melanoma. Might benefit from FISH or CGH if available depending on results of IHC.  Great meeting at St John's today mind boggling on the developments in melanocytic!

I looked again at work on a decent monitor and I'd call it a "clonal" naevus, combined naevus or naevus with phenotypic heterogeneity i.e. a background ordinary naevocellular naevus (probably BRAF mutated which would be mutually exclusive with the Spitz group). The pigmented epithelioid clone has taken a further step but is not frankly malignant in these images. Might be a DPN clone (Beta-catenin would be of interest).