Case Number : Case 1427- 11 December Posted By: Guest

I see a deep granuloma composed by histiocytes with some palisading and giant cells. The necrotic center in some pictures, like picture 3, reminds me the fibrinoid type. My first hypothesis is Rheumatoid nodule. Special stains for microorganisms are important.

Extensive fibrinoid necrosis with peripheral lymphocytic, histolytic and giant cell infiltration. In second image there is a necrotising vasculitis. I need some clinical correlation, thinking, first of all, to a Wegener Granulomatosis...

"histiocytic", no histolytic, sorry!

Agree with rheumatoid nodule (wonder whats the catch??!!)

Loong time since I have managed to visit the site. Hopefully will be more regular from now. R.Nodule is my first thought too!

agree with rheumatoid nodule but as Igor said would make special stains before signing out

Agree with rheumatoid nodule, after exclusion of infections.

Seems I got you all again!!

I had met the patient at a regional meeting in 2009 long-standing history of nodules with crusts, unilateral overlying elbow.  She was otherwise well and the case had been presented for ?diagnosis.  ?GA, ?Atypical mycobacterial, ?fungal, ?Other.  Based on images presented at the meeting I had suggested perforating granuloma annulare and heard no more until...

She was re-biopsied in 2014 with the history supplied to you. 

The lesions have persisted and due to clinical concern (for a neoplasm etc) I was invited to see the sections this year. 

My report as follows:

Reviewing the original histology, this does have features of circumscript areas of distinct collagen necrobiosis with palisading granulomatous reaction and a surface transepidermal elimination via follicles.  All these features are typical of granuloma annulare. 

The more recent histology is a rather striking deep, dermal / subcutaneous necrobiotic nodule, in keeping with the subcutaneous variant of granuloma annulare (pseudo-rheumatoid nodule).  The lack of neutrophilic infiltrate is certainly against any infective condition.  We ascertained that there was a case series of adults with juxta-articular pseudo-rheumatoid nodules, these usually are in relation to the joints of the hands.  I am uncertain if cases have been reported related to the elbow.

This case prompted me to review the prior dermpathpro cases:

https://dermpathpro.com/spot-diagnosis-1/_/2015-spot-diagnoses/august-2015/case-1334-04-august-r1388

https://dermpathpro.com/spot-diagnosis-1/_/2014-spot-diagnoses/november-2014/case-1150-19th-november-r1194

https://dermpathpro.com/spot-diagnosis-1/_/2014-spot-diagnoses/january-2014/case-925-8th-january-r963

And also to review cases from my slide collection and photographed cases from the UK National skin EQA.

Turns out I have seen another case of superficial GA on the unilateral elbow previously with similar histology to this patients biopsy from 2009 (striking red necrobiotic foci, fairly closely opposed by distinct areas without muicin) and I had contacted the general practioner who confirmed patient was otherwise well as I had considered rheumatoid.  Case P270 from the UK national EQA was considered to be a rheumatoid nodule (it had plenty of mucin).  Uma's case 1134 looks like GA with mucin but lesions were bilateral and patient had rheumatoid and you all agreed rheumatoid nodule.  So my conclusion is you can have both strikingly red palisaded GA (+/- pseudorheumatoid nodules) and Rheumatoid nodules with and without mucin and we need clinico-pathological correlation.  It appears you can have pseudorheumatoid (GA) nodules on the unilateral elbow.  If anyone can supply other cases may be worth publishing them.

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