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'''Neurofibroma''' is an uncommon [[skin]] lesion. This article also includes '''plexiform neurofibroma'''. | |||
==General== | |||
*May be a part of [[neurofibromatosis]] 1 (NF1). | |||
*A [[painful skin lesion]]. | |||
*Composed of Schwann cells, axons, fibrous material.<ref name=pmid17893219/> | |||
Classification:<ref name=pmid15486243>{{Cite journal | last1 = Wilkinson | first1 = LM. | last2 = Manson | first2 = D. | last3 = Smith | first3 = CR. | title = Best cases from the AFIP: plexiform neurofibroma of the bladder. | journal = Radiographics | volume = 24 Suppl 1 | issue = | pages = S237-42 | month = Oct | year = 2004 | doi = 10.1148/rg.24si035170 | PMID = 15486243 }}</ref> | |||
#Localized - sporatic. | |||
#Diffuse - usually poorly defined, young adults and children; sporatic. | |||
#Plexiform - associated with NF1. | |||
==Gross/radiologic== | |||
Gross features (plexiform NF):<ref name=pmid15486243>{{Cite journal | last1 = Wilkinson | first1 = LM. | last2 = Manson | first2 = D. | last3 = Smith | first3 = CR. | title = Best cases from the AFIP: plexiform neurofibroma of the bladder. | journal = Radiographics | volume = 24 Suppl 1 | issue = | pages = S237-42 | month = Oct | year = 2004 | doi = 10.1148/rg.24si035170 | PMID = 15486243 }}</ref> | |||
*"Bag of worms" appearance. | |||
Radiologic:<ref name=pmid15486243/> | |||
*Fusiform mass. | |||
==Microscopic== | |||
Features: | |||
*Spindle cells with wavy nuclei without pleomorphism - '''key feature'''. | |||
**Often described as "shredded carrots". | |||
*May be arranged in fascicles and intermixed with collagen. | |||
**Often no pattern is apparent. | |||
*Moderate increase of cellularity vis-a-vis normal dermis. | |||
*May be poorly or well-circumscribed. | |||
*+/-Plexiform growth pattern - "bag of worms".<ref name=pmid17893219/> | |||
**Multiple well-circumscribed nests. | |||
*Mast cells<ref name=pmid20233971>{{Cite journal | last1 = Staser | first1 = K. | last2 = Yang | first2 = FC. | last3 = Clapp | first3 = DW. | title = Mast cells and the neurofibroma microenvironment. | journal = Blood | volume = 116 | issue = 2 | pages = 157-64 | month = Jul | year = 2010 | doi = 10.1182/blood-2009-09-242875 | PMID = 20233971 }}</ref> - one has to look for them at high power. | |||
**Very useful for confirming the low power suspicion. | |||
DDx: | |||
*[[Plexiform neurofibroma]]. | |||
*[[Schwannoma]]. | |||
*[[Dermatofibrosarcoma protuberans]] (DFSP) - S-100 -ve. | |||
*[[Ganglioneuroma]]. | |||
*Neurotized [[melanocytic nevus]] - melanocyte nests make the diagnosis, otherwise immunostains are needed to differentiate.<ref name=pmid693815>{{Cite journal | last1 = Gray | first1 = MH. | last2 = Smoller | first2 = BR. | last3 = McNutt | first3 = NS. | last4 = Hsu | first4 = A. | title = Neurofibromas and neurotized melanocytic nevi are immunohistochemically distinct neoplasms. | journal = Am J Dermatopathol | volume = 12 | issue = 3 | pages = 234-41 | month = Jun | year = 1990 | doi = | PMID = 1693815 }}</ref> | |||
**Usually have more [[mast cell]]s than neurofibromas.<ref name=pmid8432898>{{Cite journal | last1 = Carr | first1 = NJ. | last2 = Warren | first2 = AY. | title = Mast cell numbers in melanocytic naevi and cutaneous neurofibromas. | journal = J Clin Pathol | volume = 46 | issue = 1 | pages = 86-7 | month = Jan | year = 1993 | doi = | PMID = 8432898 }}</ref> | |||
===Images=== | |||
<gallery> | |||
Image:Neurofibroma_(1).jpg | Neurofibroma - low mag. (WC) | |||
Image:Neurofibroma_(2).jpg | Neurofibroma - intermed. mag. (WC) | |||
Image:Neurofibroma_(3).jpg | Neurofibroma - high mag. (WC) | |||
</gallery> | |||
www: | |||
*[http://radiographics.rsna.org/content/24/suppl_1/S237/F9.expansion.html Plexiform neurofibroma (rsna.org)]. | |||
*[http://radiographics.rsna.org/content/24/suppl_1/S237/F10.expansion.html Plexiform neurofibroma (rsna.org)]. | |||
*[http://path.upmc.edu/cases/case304/micro.html Plexiform neurofibroma - several images (upmc.edu)]. | |||
*[http://eyewiki.aao.org/File:Orbital_Neurofibroma_-_S100.JPG Neurofibroma - S-100 (eyewiki.aao.org)]. | |||
==IHC== | |||
Features:<ref name=pmid12692193>{{cite journal |author=Hirose T, Tani T, Shimada T, Ishizawa K, Shimada S, Sano T |title=Immunohistochemical demonstration of EMA/Glut1-positive perineurial cells and CD34-positive fibroblastic cells in peripheral nerve sheath tumors |journal=Mod. Pathol. |volume=16 |issue=4 |pages=293–8 |year=2003 |month=April |pmid=12692193 |doi=10.1097/01.MP.0000062654.83617.B7 |url=http://www.nature.com/modpathol/journal/v16/n4/full/3880761a.html }}</ref> | |||
*S100 +ve -- wavy pattern.<ref name=pmid22742554>{{Cite journal | last1 = Chen | first1 = Y. | last2 = Klonowski | first2 = PW. | last3 = Lind | first3 = AC. | last4 = Lu | first4 = D. | title = Differentiating neurotized melanocytic nevi from neurofibromas using Melan-A (MART-1) immunohistochemical stain. | journal = Arch Pathol Lab Med | volume = 136 | issue = 7 | pages = 810-5 | month = Jul | year = 2012 | doi = 10.5858/arpa.2011-0335-OA | PMID = 22742554 }} | |||
</ref> | |||
*CD34 +ve. | |||
*Glut1 +ve. | |||
*EMA +ve/-ve. | |||
*NF +ve/-ve.<ref name=pmid22742554/> | |||
*MART-1 -ve.<ref name=pmid22742554/> | |||
**Positive in neurotized melanocytic nevi. | |||
==Sign out== | |||
<pre> | |||
FOURTH TOE, LEFT, EXCISION: | |||
- NEUROFIBROMA. | |||
</pre> | |||
===Micro=== | |||
The sections show skin with a lesion composed of irregular-shaped groups of bland dermal spindle cells with wavy nuclei and pale-eosinophilic cytoplasm. Mast cells are seen scattered throughout the lesion. Thick collagen separates the clusters of the spindle | |||
cells. There is no nuclear atypia. Mitotic activity is not appreciated. No melanocytic nests are identified. | |||
The overlying epidermis matures to the surface. | |||
====Alternate==== | |||
The sections show skin with an unencapsulated dermal spindle cell lesion with navy nuclei that have a likeness to shredded carrots. Occasional mast cells are present within the lesion. There is no nuclear atypia. Mitotic activity is not appreciated. No melanocytic nests are identified. | |||
==See also== | |||
*[[Peripheral nerve sheath tumour]]. | |||
==References== | |||
{{Reflist|2}} | |||
[[Category:Peripheral nerve sheath tumours]] | |||
[[Category:Diagnosis]] | [[Category:Diagnosis]] |
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