What made me think it was malignant transformation of a KA is that the regression crateriform area has different ihc pattern, with wt p16 and p53, and very low ki-67.

Do you think it is invasive or in situ? I struggle with this kinda"pushing" lesions...

Immuno. Ki-67 not pictured (was low on the crateriform area, and very high on the atypical zona).

I belive this is a SCC arising on a keratoacanthoma. What do you think @racarr51.bsky.social ?

Detail of the atypical area

Trichilemmal Carcinoma?

Yes, but the online version has now changed to the "print" versión, so there's no p16 anymore either :( fortunately I have your papers!

Hi! Why did they not include info and patterns of p16 in the print version of the WHO Skin blue book? There were some hints in the former beta version but no mention at all in the actual print version...