Case Number : Case 2801- 1 April 2021 Posted By: Saleem Taibjee

There is an interstitial pattern of granulomatous dermal inflammation which includes prominent neutrophils.  I think this would fit into the description of (not very) palisaded neutrophilc granulomatous dermatitis.  With the history of leg ulceration I would consider rheumatoid disease as a recognised association.

Characteristic site of palisaded neutrophilic and granulomatous dermatitis.. 

Not all of the images have been posted. I'll ask if this can be done.

I should have also said ... You're in the right ballpark, but I think can be more specific.

Palisaded neutrophilic interstitial granulomatosis...with some resembling Wegener granulomatosis, but I don’t see any vasculitis. 

You're a hard taskmaster Saleem!

Richard, this is how you like it! Vincenzo has shown the way... Unfortunately there is an issue with DermpathPro at the moment, ordinarily I would be able to upload images directly, including the nice clinical images on this case, but I am unable to at the moment.

Always enjoy the cases posted on dermpathpro here, and Thank you all for the contribution of nice cases for education purposes. Dr Saleem always have interesting cases and I love your high quality images and detailed explanation. For this case, I would agree the thought process if Dr Logan and Dr Vincenzo's ideas of PNGD. however, for this kind of lesions, when I saw a little cytologic atypia with mitosis (like seen in this case), I would throw some CK and EMA there just not want to miss epithelioid sarcoma.  

Hi. It's a shame that the additional images including clinical photos have not appeared.

The patient has scabby nodules on his elbows, and large irregular ulcers on his legs with eschar.

He is known to have granulomatosis with polyangiitis (Wegeners), with nasal sinus disease and lung manifestations. The cutaneous features are more recent.

The histology is very characteristic, with 'basophilic' 'geographic' palisading granulomas very suggestive of this specific disease. This contrasts with more eosinophilic but similar geographical areas we might see in allergic granulomatosis with vasculitis (Churg-Strauss). The hypothesis is that the curious pattern of collagen necrosis arises due to vasculitis and resultant tissue ischaemia. It probably does represent a subset of palisaded neutrophilic granulomatous dermatitis, but I think the basophilic collagen necrosis is a more specific clue to this particular underlying diagnosis.

Very instructive as usual. Thank you Saleem.

The clinical images and other histology images have now been posted for this case above

Thanks Dr

Thanks , Saleem.