View source for Nasal cavity and paranasal sinuses

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|author1=[[User:Mikael Häggström|Mikael Häggström]]
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==Nasal or sinonasal polyps==
Look for signs of malignancy.
{{Further|Evaluation of suspected malignancies}}
[[File:Histopathology of a nasal polyp.jpg|thumb|'''Benign nasal/sinonasal polyp''' (not otherwise specified), consisting of hyperplastic edematous connective tissue with some seromucous glands and inflammation (mostly neutrophils and eosinophils), surrounded by respiratory or squamous epithelium.<ref>{{Cite book|url=https://books.google.com/books?id=Zm3jBwAAQBAJ&pg=PA168|title=Ear, Nose and Throat Histopathology|last=Michaels|first=Leslie|date=2012-12-06|publisher=Springer Science & Business Media|isbn=9781447133322|language=en|page=168}}</ref> It can be termed '''inflammatory nasal/sinonasal polyp''' when inflammation is more pronounced.]]

Main differential diagnoses:
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File:Histopathology of inverted papilloma.jpg|'''Inverted papilloma''', wherein the surface epithelial cells grow downward into the underlying supportive tissue.
File:Histopathology of nasal squamous papilloma.jpg|'''Squamous papilloma''', with acanthosis and hyperkerratosis.
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In case of significant '''inflammation''':
*Take at least one high magnification look to confirm that it is mixed and that lymphocytes are not atypical (otherwise, consult hematopathology, particularly whether it could be a lymphoma, notably extranodal NK/T cell lymphoma, nasal type.
*{{Moderate-begin}}Classify as '''acute''' (with neutrophils) versus '''chronic''' (lymphocytes, eosinophils and/or plasma cells). Also look at any bone fragments for osteomyelitis.{{Moderate-end}} {{further|Osteomyelitis}}
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File:Histopathology of sinonasal inflammatory polyp with mixed inflammation, annotated.jpg|'''Benign chronic mixed inflammation''' of an inflammatory sinonasal polyp.
File:Histopathology of acute sinusitis.png|'''Acute inflammation''' characterized by neutrophils.
File:Histopathology of extranodal NK-T cell lymphoma, nasal type.png|'''Extranodal NK/T cell lymphoma, nasal type'''.<ref>{{cite journal| author=Takahara M, Kumai T, Kishibe K, Nagato T, Harabuchi Y| title=Extranodal NK/T-Cell Lymphoma, Nasal Type: Genetic, Biologic, and Clinical Aspects with a Central Focus on Epstein-Barr Virus Relation. | journal=Microorganisms | year= 2021 | volume= 9 | issue= 7 | pages=  | pmid=34202088 | doi=10.3390/microorganisms9071381 | pmc=8304202 | url=https://www.ncbi.nlm.nih.gov/entrez/eutils/elink.fcgi?dbfrom=pubmed&tool=sumsearch.org/cite&retmode=ref&cmd=prlinks&id=34202088  }}<br>- "This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY) license (https://creativecommons.org/licenses/by/4.0/)."</ref> These lymphoma cells are typically monotonous, with folded nuclei, indistinct nucleoli and moderate amount of cytoplasm.<ref>{{cite web|url=https://www.pathologyoutlines.com/topic/lymphomanonBnasal.html|title=Extranodal NK / T cell lymphoma, nasal type|author=Mario L. Marques-Piubelli, M.D., Carlos A. Torres-Cabala, M.D., Roberto N. Miranda, M.D.|website=Pathology Outlines}} Last author update: 5 January 2021. Last staff update: 14 October 2021</ref>
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==Reporting==
Example:
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| [[File:Histopathology of nasal contents with chronic inflammation.jpg|210px|left]] Right and left sinus contents, excisions:<br>Benign respiratory mucosa with chronic inflammation.<br>Bone without significant histopathologic changes.
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