View source for Rheumatoid nodule

{{ Infobox diagnosis
| Name       = {{PAGENAME}}
| Image      = Rheumatoid_nodule_-_intermed_mag_2.jpg
| Width      =
| Caption    = Rheumatoid nodule. [[H&E stain]].
| Synonyms   =
| Micro      = necrotic collagen bundles with fibrin surrounded by [alisading [[granuloma]], +/-[[eosinophil]]s
| Subtypes   =
| LMDDx      = [[granuloma annulare]], [[necrobiosis lipoidica]]
| Stains     = [[Alcian blue stain|Alcian blue]] (pH 2.5) -ve
| IHC        =
| EM         =
| Molecular  =
| IF         =
| Gross      = extensor aspect of the extremities, e.g. dorsal aspect of elbow
| Grossing   =
| Site       = [[skin]]
| Assdx      =
| Syndromes  =
| Clinicalhx =
| Signs      = skin nodule, close to joint - typically elbow
| Symptoms   =
| Prevalence = uncommon
| Bloodwork  = RF +ve
| Rads       =
| Endoscopy  =
| Prognosis  = benign
| Other      =
| ClinDDx    =
| Tx         = 
}}
{{ Infobox external links
| Name           = Rheumatoid nodule
| EHVSC          = 10182
| pathprotocols  = 
| wikipedia      =
| pathoutlines   =
}}
'''Rheumatoid nodule''', abbreviated '''RN''', is a [[skin]] manifestation of [[rheumatoid arthritis]].

Nodules in the [[lung]] associated with rheumatoid arthritis are dealt with in ''[[rheumatoid lung nodule]]''.

==General==
*Seen in [[rheumatoid arthritis]] - usually only in seropositive cases, i.e. ''rheumatoid factor'' (RF) positive.<ref name=Ref_DCHH299>{{Ref DCHH|299}}</ref>
**Exceptions are reported.<ref name=pmid6364806>{{Cite journal  | last1 = Kaye | first1 = BR. | last2 = Kaye | first2 = RL. | last3 = Bobrove | first3 = A. | title = Rheumatoid nodules. Review of the spectrum of associated conditions and proposal of a new classification, with a report of four seronegative cases. | journal = Am J Med | volume = 76 | issue = 2 | pages = 279-92 | month = Feb | year = 1984 | doi =  | PMID = 6364806 }}</ref>

==Gross==
*Usually on the extensor aspect of the extremities, e.g. dorsal aspect of elbow.<ref name=Ref_Derm53>{{Ref Derm|53}}</ref>
*Typically close to a joint.{{fact}}

==Microscopic==
Features:<ref name=Ref_DCHH299>{{Ref DCHH|299}}</ref><ref name=Ref_Derm52>{{Ref Derm|52}}</ref>
*Necrotic collagen bundles with fibrin surrounded by:
**Palisading [[granuloma]].
*+/-Eosinophils.

Notes:
*Histomorphologically very similar to ''[[Granuloma annulare]]''. 

DDx:
*[[Granuloma annulare]] - has mucin in the core of the granuloma.<ref name=Ref_Derm52>{{Ref Derm|52}}</ref>
*[[Necrobiosis lipoidica]].

===Images===
www:
*[http://granuloma.homestead.com/rheumatoid_nod_S89-2617-1.jpg Rheumatoid nodule (granuloma.homestead.com)].<ref name=ghc>URL: [http://granuloma.homestead.com/palisading.html http://granuloma.homestead.com/palisading.html]. Accessed on: 1 November 2010.</ref>
*[http://granuloma.homestead.com/rheumatoid_nod_S89-2617-5.jpg Rheumatoid nodule (granuloma.homestead.com)].<ref name=ghc>URL: [http://granuloma.homestead.com/palisading.html http://granuloma.homestead.com/palisading.html]. Accessed on: 1 November 2010.</ref>
*[http://library.med.utah.edu/WebPath/jpeg3/BONE045.jpg Rheumatoid nodule (utah.edu)].<ref>URL: [http://www.pathguy.com/lectures/joints.htm http://www.pathguy.com/lectures/joints.htm]. Accessed on: 1 November 2010.</ref>
<gallery>
Image:Rheumatoid_nodule_-_low_mag.jpg |Rheumatoid nodule - low mag. (WC)
Image:Rheumatoid_nodule_-_intermed_mag_2.jpg |Rheumatoid nodule - intermed. mag. (WC)
Image:Rheumatoid_nodule_-_high_mag.jpg |Rheumatoid nodule - high mag. (WC)
</gallery>

==Stains==
*[[Alcian blue stain|Alcian blue]] (pH 2.5) -ve.
**Positive staining of mucin in [[granuloma annulare]].<ref name=pmid20523767>{{Cite journal  | last1 = Yun | first1 = JH. | last2 = Lee | first2 = JY. | last3 = Kim | first3 = MK. | last4 = Seo | first4 = YJ. | last5 = Kim | first5 = MH. | last6 = Cho | first6 = KH. | last7 = Kim | first7 = MB. | last8 = Lee | first8 = WS. | last9 = Lee | first9 = KH. | title = Clinical and pathological features of generalized granuloma annulare with their correlation: a retrospective multicenter study in Korea. | journal = Ann Dermatol | volume = 21 | issue = 2 | pages = 113-9 | month = May | year = 2009 | doi = 10.5021/ad.2009.21.2.113 | PMID = 20523767 | PMC = 2861218 }}</ref>

==Sign out==
<pre>
Lesion (subcutaneous), right index finger, excision:
- Palisading granulomas with cores of necrobiotic collagen, consistent with rheumatoid nodule.
</pre>

===Micro===
The sections show foci with strands of necrobiotic collagen surrounded by palisading granulomas. Rare Neutrophils are seen in the core of the granulomas. Multinucleated cells are not apparent. 

Benign fibroadipose tissue and dense connective tissue are also present.

==See also==
*[[Rheumatoid arthritis]].
*[[Rheumatoid lung nodule]].

==References==
{{Reflist|1}}

[[Category:Diagnosis]]