Case Number : Case 2217 - 7 December 2018 Posted By: Dr. Richard Carr

fever with rash and biopsy shows dermal edema with small vessel vasculitis with mixed inflammation with lymphocytes and a few eosinophils. fibrin deposition seen around vessels

Possible infective cause due to bacteria/rickettsial infections possibly

Difficult for me!  It seems a Sweet Syndrome , but Vasculitis doesn’t fit well. Eosinophils and vasculitis would be more in keeping with Churg Strauss but no Asthma.  Flames figures would be in keeping with Wells syndrome but with CS disease also.  Favore a Sweet syndrome with eosinophils and vasculitis for silhouette and other histological findings but not sure. 

Humm. It seem like a vasculitis whit granulomas (my impression) and flame figures (in keep whit eosinophils i think) so my interpretation is Eosinophilic granulomatosis with Polyangitis. But Im agree that is a difficult case.

Maybe the secret to find our rosebud is in the last picture : cutaneous Well's syndrome in visceral larva migrans??? But doesn't fit clinically ( why symmetrical? )...No. SS is yet my favorite spot.

There are a few necrotic keratinocytes. This could be drug induced erythema multiforme. IF can be negative in EM

Found this:

Flame figures in linear IgA bullous dermatosis: a novel histopathologic finding.

Acute Febrile Neutrophilic Dermatosis - Sweet’s Syndrome (SS). Without the clinical information it would be difficult to suspect this with confident.

Vasculitis can be seen as an epiphenomenon or a secondary process in SS and one should not exclude SS if other features consist with this diagnosis.

Some of the mononuclear cells which may look like histiocytes “histiocytoid” can be immature granulocyte precursors, MPO and other markers can guide their lineage in doubtful cases.

looking at the marked dermal edema, it could be sweet syndrome

This case was from an external quality assurance scheme and had to be removed from scoring due to lack of consensus.

The slightly favoured response was leucocytoclastic vasculitis (44%) with Sweet's syndrome / neutrophilic dermatosis a close second (40%), and Vasculitis (26%) a moderate 3rd.

Other suggestions (all <1% unless stated, probably differentials) included: Sweet's with LCV (1.9%); Granulomatous vasculitis; Necrotising vasculitis; Erysipleas/cellulitis; Palisaded neutrophilic granulomatous dermatitis; EM, DH, Kikuchi, suppurative granulomatous; TEN, Stevens-Johnson; EBA; pyoderma gangrenosum; lupus; BP; fixed drug; Cowpox; EED; eosinophilic cellulitis.

My personal response: Leucocytoclastic vasculitis (Sweet's variant), commenting: Clinical sounds like Sweet's, histology is more LCV! I guess it's academic. 

Certainly Bernhard Zelger a mentor for vasculitis/vasuolopathy considers Sweet's as a type of LCV.

Regarding the pathology as Sweet's evolves it becomes vaguely granulomatous. This is fibrin (not a flame figure, eosinophils are not seen to any degree). I don't think this is the histiocytoid variant (which we have seen in dermpathpro).

Nice Case and great discussion by Dr. Carr and the other colleagues.

I learn more of Sweet Syndrome today.

Nice case. My first and last impression is hypersentivity leucocytoclastic vasculitis due to previous infection.