Case Number : Case 2652 - 04 September 2020 Posted By: Dr. Richard Carr

There is obviously a perforating disorder going on here, with quite a lot of neutrophils in the stratum corneum.  The small amount of dermis visible has a granulomatous look to it, perhaps with a hint of necrobiosis.  Given the site I would hazard a guess at perforating GA.  Palisaded neutrophilic granulomatous dermatitis or fish-tank granuloma would also have to be considered.

One more thought - the small "necrobiotic" dermal foci have a somewhat feathery look to them.  Gout comes into the equation.

1 hour ago, Richard Logan said:

One more thought - the small "necrobiotic" dermal foci have a somewhat feathery look to them.  Gout comes into the equation.

Yes. Gout Tophus. 

Beautiful one!

Agree. Gout Tophus with transepidermal elimination

Yes. Gout with transepidermal elimination

yes gout agree

Gout Tophus with transepidermal elimination is my thought.

Well done Richard. You rescued that one. If I'm right you mentioned you are a head & neck / oral pathologist so would not see gout often although I've seen a few cases on the pinna of the ear. I think this is a nice example of a pathology being quite distinctive even though the focus is tiny one can make a confident spot diagnosis. 

Actually I'm a retired Dermatologist, no special pathological training, as you can tell!

16 hours ago, Richard Logan said:

Actually I'm a retired Dermatologist, no special pathological training, as you can tell!

Hello Richard Logan. I’m a retired ( general pathologist ) as well. 

Ciao Vincenzo, piacere di conoscerti

Huge respect for getting this subtle pathology!