Case Number : Case 2567 - 08 May 2020 Posted By: Dr. Richard Carr

Punctate keratoderma?

Porokeratotic eccrine ostial and dermal duct nevus

Spiny keratoderma

focal Invaginated orthohyperkeratotic column resembling coronoid lamellae, but with no parakeratosis. there is no dermal inflammation

Think of type 1 punctate palmo-plantar keratoderma

Well thanks all for attempting a "keratoderma" differential. I was fairly confident of the diagnosis of palmoplantar keratoderma (as suggested by clinical colleague) and issued my report as such. I was lucky to be able to refer to a wonderful PDF of a lecture given to the National Skin EQA by Professor Dieter Metze.

Given that I was sharing the case and I would not consider myself expert on keratodermas I asked Dieter Metze for his opinion on the images.

He kindly writes as follows:

Dear  Richard, 
clinically and histologically a very typical case of Palmoplantar keratoderma punctata, type I (PPK papulosa, PPK dissipatum, 
PPK Buschke-Fischer-Brauer). No signs of verruca (although the silhouette with inward bending of the rete ridges is a look alike!)
Very often manifestation is late.
Best regards
Dieter

Agree with @AmerSM, there is some epidermal invagination with an overlying parakeratotic and broad cornoid lamella, just above an acrosiringyum with tortous contours. Porokeratotic eccrine ostial and dermal duct nevus.