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| __NOTOC__ | | __NOTOC__ |
| {{SI}} | | {{Pleomorphic adenoma}} |
| {{CMG}}; {{AE}} {{MV}}; {{TarekNafee}}
| | '''For patient information, click [[Pleomorphic adenoma (patient information)|here]]''' |
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| {{SK}} Pleomorphic adenoma of the salivary glands; BMT; Benign mixed tumors of the salivary gland
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| ==Overview==
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| '''Pleomorphic adenoma''' (also known as "Benign mixed tumor of the salivary gland") is a benign neoplastic tumor of the [[salivary gland]]s. Pleomorphic adenoma is the most common type of salivary gland tumor and the most common tumor of the [[parotid gland]].<ref name="radiographics">Ewa J. Bialek, Wieslaw Jakubowski, Piotr Zajkowski, Kazimierz T. Szopinski, and Antoni Osmolski. [http://radiographics.rsnajnls.org/cgi/content/abstract/26/3/745 US of the Major Salivary Glands: Anatomy and Spatial Relationships, Pathologic Conditions, and Pitfalls.] RadioGraphics 2006 26: 745-763. </ref> Pleomorphic adenoma was first described by Beahrs in 1957.<ref name="pmid25565746">{{cite journal |vauthors=Keerthi R, Raut RP, Vaibhav N, Ghosh A |title=Carcinoma ex pleomorphic adenoma: Diagnostic dilemma and treatment protocol |journal=Indian J Dent |volume=5 |issue=3 |pages=157–60 |year=2014 |pmid=25565746 |pmc=4213878 |doi=10.4103/0975-962X.140840 |url=}}</ref> Pleomorphic adenoma may be classified according to anatomical distribution into 4 groups: [[parotid gland]] pleomorphic adenoma, submandibular gland pleomorphic adenoma, [[Minor salivary gland cancer|minor salivary gland]] pleomorphic adenoma, and [[sublingual gland]] pleomorphic adenoma. The pathogenesis of pleomorphic adenoma is characterized by an admixture of polygonal epithelial and spindle-shaped myoepithelial elements. A mutation on the PLAG1 gene is associated with the development of pleomorphic adenoma. Pleomorphic adenoma is common and it accounts for 60% of all parotid gland tumors (represents 45-75% of all [[Salivary gland tumor|salivary gland neoplasms]]). The incidence of pleomorphic adenoma is approximately 2-3.5 per 100,000 individuals worldwide. The most characteristic clinical feature of pleomorphic adenoma is a painless single-nodular parotid mass. Pleomorphic adenoma may be initially asymptomatic. Common symptoms of pleomorphic adenoma may include [[xerostomia]], dysphagia, and painful chewing. MRI is the imaging modality of choice for pleomorphic adenoma. Surgical excision in conjunction with pre-surgical biopsy is the most common approach to the management of pleomorphic adenoma. The recurrence rate after surgery will depend on the histological subtype (mixed pleomorphic adenomas have a higher recurrence rate). In some cases, patients with pleomorphic adenoma may receive medications to stimulate saliva production such as [[Pilocarpine|pilocarpin]] and [[cevimeline]] for symptomatic relief.
| | {{CMG}}; {{AE}} {{M.N}} |
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| ==Historical Perspective==
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| Pleomorphic adenoma was first described by Beahrs in 1957.<ref name="pmid25565746">{{cite journal |vauthors=Keerthi R, Raut RP, Vaibhav N, Ghosh A |title=Carcinoma ex pleomorphic adenoma: Diagnostic dilemma and treatment protocol |journal=Indian J Dent |volume=5 |issue=3 |pages=157–60 |year=2014 |pmid=25565746 |pmc=4213878 |doi=10.4103/0975-962X.140840 |url=}}</ref><ref name="pmid13457639">{{cite journal| author=BEAHRS OH, WOOLNER LB, KIRKLIN JW, DEVINE KD| title=Carcinomatous transformation of mixed tumors of the parotid gland. | journal=AMA Arch Surg | year= 1957 | volume= 75 | issue= 4 | pages= 605-13; discussion 613-4 | pmid=13457639 | doi= | pmc= | url=http://www.ncbi.nlm.nih.gov/entrez/eutils/elink.fcgi?dbfrom=pubmed&tool=sumsearch.org/cite&retmode=ref&cmd=prlinks&id=13457639 }} </ref>
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| ==Classification== | | ==[[Pleomorphic adenoma overview|Overview]]== |
| Pleomorphic adenoma may be classified according to anatomical distribution into 4 groups:<ref name="comp">Pleomorphic adenoma. Wikipedia. https://en.wikipedia.org/wiki/Pleomorphic_adenoma. Accessed on April 25, 2016</ref>
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| *[[Parotid gland]] pleomorphic adenoma (80%)
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| :*Superficial lobe pleomorphic adenoma (most common)
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| *[[Submandibular gland]] pleomorphic adenoma
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| *Minor [[salivary gland]] pleomorphic adenoma
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| *[[Sublingual gland]] pleomorphic adenoma
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| Pleomorphic adenoma may also be classified according to histological type into 3 subtypes:<ref name="comp">Pleomorphic adenoma. Wikipedia. https://en.wikipedia.org/wiki/Pleomorphic_adenoma. Accessed on April 25, 2016</ref>
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| *Mixed (hypocellular)
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| *Cellular
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| *Classic
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| [[Lacrimal gland]] pleomorphic adenoma is a variant of pleomorphic adenoma which accounts for approximately 50% of [[lacrimal gland]] [[tumors]].<ref name="comp">Pleomorphic adenoma. Libre Pathology. https://librepathology.org/wiki/Pleomorphic_adenoma Accessed on April 25, 2016</ref>
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| ==Pathophysiology== | | ==[[Pleomorphic adenoma historical perspective|Historical Perspective]]== |
| ===Pathogenesis===
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| The pathogenesis of pleomorphic adenoma is characterized by an admixture of polygonal epithelial and spindle-shaped myoepithelial elements.<ref name="comp">Pleomorphic adenoma. Wikipedia. https://en.wikipedia.org/wiki/Pleomorphic_adenoma. Accessed on April 25, 2016</ref>
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| ===Genetics=== | | ==[[Pleomorphic adenoma classification|Classification]]== |
| The mutation on [[PLAG1]] gene has been associated with the development of pleomorphic adenoma.<ref name="comp">Pleomorphic adenoma. Libre Pathology. https://librepathology.org/wiki/Pleomorphic_adenoma Accessed on April 25, 2016</ref>
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| ===Gross Pathology===
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| On gross pathology, characteristic findings of pleomorphic adenoma include:<ref name="comp">Pleomorphic adenoma. Libre Pathology. https://librepathology.org/wiki/Pleomorphic_adenoma Accessed on April 25, 2016</ref>
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| *May have [[cartilaginous]] appearance
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| *Typically well-circumscribed
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| *Tumor is usually enveloped by a fibrous capsule
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| ===Microscopic Pathology===
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| On '''microscopic histopathological analysis''', characteristic findings of pleomorphic adenoma include:<ref name="comp">Pleomorphic adenoma. Libre Pathology. https://librepathology.org/wiki/Pleomorphic_adenoma Accessed on April 25, 2016</ref>
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| *Mixture of [[epithelial]] and [[myoepithelial]] elements
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| *Background stroma that may be mucoid, mixed, [[cartilaginous]], or [[hyaline]]
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| *Epithelial elements may be arranged in duct-like structures, sheets, clumps and/or interlacing strands
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| *Epithelial elements consist of polygonal, spindle or stellate-shaped cells (hence pleomorphism)
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| On '''immunohistochemical analysis''', characteristic findings of pleomorphic adenoma include:<ref name="comp">Pleomorphic adenoma. Libre Pathology. https://librepathology.org/wiki/Pleomorphic_adenoma Accessed on April 25, 2016</ref>
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| *Positive [[S-100 protein]]
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| *Positive SMA
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| *Positive [[GFAP]]
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| ==Causes== | | ==[[Pleomorphic adenoma pathophysiology|Pathophysiology]]== |
| There are no established causes for pleomorphic adenoma.
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| ==Differentiating Pleomorphic Adenoma from Other Diseases== | | ==[[Pleomorphic adenoma causes|Causes]]== |
| Pleomorphic adenoma must be differentiated from other diseases that cause [[xerostomia]], single-nodular parotid mass, and dysphagia such as: | |
| *[[Warthin's tumor]]
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| *[[Mucoepidermoid carcinoma]]
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| *Myoepithelioma
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| *[[Adenoid]] cystic carcinoma
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| ==Epidemiology and Demographics== | | ==[[Pleomorphic adenoma differential diagnosis|Differentiating Pleomorphic Adenoma from other Diseases]]== |
| ===Epidemiology===
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| *Pleomorphic adenoma accounts for 60% of all parotid gland tumors and represents 45-75% of all salivary gland neoplasms.
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| *The [[incidence]] of pleomorphic adenoma is approximately 2-3.5 per 100,000 individuals worldwide.
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| ===Age=== | | ==[[Pleomorphic adenoma epidemiology and demographics|Epidemiology and Demographics]]== |
| *Pleomorphic adenoma is more commonly observed among patients aged 60 to 70 years old.
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| *Pleomorphic adenoma is less commonly observed in children.
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| ===Gender=== | | ==[[Xyz risk factors|Risk Factors]]== |
| *Pleomorphic adenoma affects men and women equally.
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| ===Race=== | | ==[[Pleomorphic adenoma screening|Screening]]== |
| *There is no racial predilection for pleomorphic adenoma.
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| ==Risk Factors== | | ==[[Pleomorphic adenoma natural history, complications and prognosis|Natural History, Complications and Prognosis]]== |
| Common risk factors in the development of pleomorphic adenoma include:<ref name="jkc">Pleomorphic adenoma. Salivary Gland Cancer Treatment–for health professionals (PDQ®).http://www.cancer.gov/types/head-and-neck/hp/salivary-gland-treatment-pdq#link/_403_toc Accessed on February 17, 2016</ref>
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| *[[Ionizing radiation]]
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| *Occupations associated with an increased risk such as:
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| **Rubber products manufacturing
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| **[[Asbestos]] mining
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| **Plumbing
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| **Some types of woodworking
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| == Natural History, Complications and Prognosis== | | ==Diagnosis== |
| ===Natural history===
| | [[Pleomorphic adenoma diagnostic study of choice|Diagnostic study of choice]] | [[Pleomorphic adenoma history and symptoms|History and Symptoms]] | [[Pleomorphic adenoma physical examination|Physical Examination]] | [[Pleomorphic adenoma laboratory findings|Laboratory Findings]] | [[Pleomorphic adenoma electrocardiogram|Electrocardiogram]] | [[Pleomorphic adenoma x ray|X-Ray Findings]] | [[Pleomorphic adenoma echocardiography and ultrasound|Echocardiography and Ultrasound]] | [[Pleomorphic adenoma CT scan|CT-Scan Findings]] | [[Pleomorphic adenoma MRI|MRI Findings]] | [[Pleomorphic adenoma other imaging findings|Other Imaging Findings]] | [[Pleomorphic adenoma other diagnostic studies|Other Diagnostic Studies]] |
| The majority of patients with pleomorphic adenoma remain asymptomatic for years. Early clinical features include [[dry mouth]], [[difficulty swallowing]], and a palpable single nodular mass. If left untreated, patients with pleomorphic adenoma may progress to develop malignant transformation.
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| ===Complications===
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| Common complications of pleomorphic adenoma include:<ref name="comp">Pleomorphic adenoma. Wikipedia. https://en.wikipedia.org/wiki/Pleomorphic_adenoma. Accessed on April 25, 2016</ref>
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| *[[Nerve injury]]
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| *Cosmetic deformity
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| *[[Hemorrhage]] or [[hematoma]]
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| *[[Frey's syndrome]]
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| ===Prognosis=== | | ==Treatment== |
| If malignant transformation occurs, prognosis is generally poor. The 5-year survival rate of patients with malignant pleomorphic adenoma is approximately 30%.<ref name="comp">Pleomorphic adenoma. Wikipedia. https://en.wikipedia.org/wiki/Pleomorphic_adenoma. Accessed on April 25, 2016</ref>
| | [[Pleomorphic adenoma medical therapy|Medical Therapy]] | [[Pleomorphic adenoma surgery|Surgery]] | [[Pleomorphic adenoma primary prevention|Primary Prevention]] | [[Pleomorphic adenoma secondary prevention|Secondary Prevention]] | [[Pleomorphic adenoma cost-effectiveness of therapy|Cost-Effectiveness of Therapy]] | [[Pleomorphic adenoma future or investigational therapies|Future or Investigational Therapies]] |
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| == Diagnosis == | | ==Case Studies== |
| | | [[Pleomorphic adenoma case study one|Case #1]] |
| === Symptoms ===
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| Pleomorphic adenoma may be initially asymptomatic. Symptoms of pleomorphic adenoma may include the following:<ref name="comp">Pleomorphic adenoma. Wikipedia. https://en.wikipedia.org/wiki/Pleomorphic_adenoma. Accessed on April 25, 2016</ref>
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| *[[Dry mouth]]
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| *[[Dysphagia causes|Dysphagia]]
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| *[[Chewing|Painful chewing]]
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| === Physical Examination ===
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| Patients with pleomorphic adenoma may present with a facial deformity. Physical examination of the head and neck may be remarkable for:<ref name="MRI"> Pleomorphic adenoma. Radiopedia. http://radiopaedia.org/cases/pleomorphic-adenoma-9 Accesed on April 28, 2016</ref>
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| *Submandibular single, mobile, painless, and firm nodular mass
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| *Eversion of the ear lobe
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| *Limited mandiblular motion
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| === Laboratory Findings ===
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| There are no specific laboratory findings associated with pleomorphic adenoma.<ref name="comp">Pleomorphic adenoma. Wikipedia. https://en.wikipedia.org/wiki/Pleomorphic_adenoma. Accessed on April 25, 2016</ref>
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| ===Imaging Findings===
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| *[[MRI]] is the imaging modality of choice for pleomorphic adenoma. On [[MRI]], characteristic findings of pleomorphic adenoma, include:<ref name="MRI"> Pleomorphic adenoma. Radiopedia. http://radiopaedia.org/cases/pleomorphic-adenoma-9 Accesed on April 28, 2016</ref><ref name="MRI"> Pleomorphic adenoma. Radiopedia. http://radiopaedia.org/cases/pleomorphic-adenoma-9 Accesed on April 28, 2016</ref>
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| :*Pleomorphic adenomas are usually well-circumscribed
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| :*Homogeneous masses with low intensity on T1-weighted images and high intensity on T2-weighted images
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| :*Commonly, a rim of decreased signal intensity on T2-weighted images is observed
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| :*After gadolinium enhancement, the tumors are homogeneously enhancing unless they are large.
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| *On CT scan, characteristic findings of pleomorphic adenoma include:
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| :*Smooth and well-marginated tumors
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| :*The attenuation values of the mass are usually homogeneous and higher than that of the surrounding gland
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| :*Tumor enhancement is variable and can result in a missed diagnosis if delayed images are not acquired
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| :**Pleomorphic adenomas are poorly enhancing in the early phase of contrast enhancement, though the amount of enhancement increases over time
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| *On [[Ultrasound]], characteristic findings of pleomorphic adenomas include:
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| :*Pleomorphic adenomas are hypoechoic, well-defined, lobulated tumors with posterior acoustic enhancement and may contain calcifications.
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| :**Ultrasound is frequently used to guide [[FNA]] or core needle [[biopsy]]<ref>{{cite journal |author=Białek EJ, Jakubowski W, Karpińska G |title=Role of ultrasonography in diagnosis and differentiation of pleomorphic adenomas: work in progress |journal=Arch Otolaryngol Head Neck Surg |volume=129 |issue=9 |pages=929–33 |year=2003 |month=Sep |pmid=12975263 |doi=10.1001/archotol.129.9.929 |url=}}</ref>
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| ====Gallery====
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| <gallery perrow="3">
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| Image:Pleomorphic adenoma MRI 101.jpg|MRI: A right parotid pleomorphic adenoma [http://www.radswiki.net Images courtesy of RadsWiki]
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| Image:Pleomorphic adenoma MRI 102.jpg|MRI: A right parotid pleomorphic adenoma [http://www.radswiki.net Images courtesy of RadsWiki]
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| Image:Pleomorphic adenoma MRI 103.jpg|MRI: A right parotid pleomorphic adenoma [http://www.radswiki.net Images courtesy of RadsWiki]
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| Image:Pleomorphic adenoma MRI 104.jpg|MRI: A right parotid pleomorphic adenoma [http://www.radswiki.net Images courtesy of RadsWiki]
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| Image:Pleomorphic adenoma MRI 105.jpg|MRI: A right parotid pleomorphic adenoma [http://www.radswiki.net Images courtesy of RadsWiki]
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| Image:Pleomorphic adenoma PET 106.jpg|PET: A right parotid pleomorphic adenoma [http://www.radswiki.net Images courtesy of RadsWiki]
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| </gallery>
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| === Other Diagnostic Studies ===
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| *Pleomorphic adenoma may also be diagnosed using [[fine needle aspiration]] (FNA) and core needle [[biopsy]].
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| *[[FNA]] can determine whether the tumor is [[malignant]] in nature with a [[sensitivity]] approximately 90%<ref>{{cite journal |author=Cohen EG, Patel SG, Lin O, ''et al'' |title=Fine-needle aspiration biopsy of salivary gland lesions in a selected patient population |journal=Arch Otolaryngol Head Neck Surg |volume=130 |issue=6 |pages=773–8 |year=2004 |month=Jun |pmid=15210562 |doi=10.1001/archotol.130.6.773 |url=}}</ref><ref>{{cite journal |author=Batsakis JG, Sneige N, el-Naggar AK |title=Fine-needle aspiration of salivary glands: its utility and tissue effects |journal=Ann Otol Rhinol Laryngol |volume=101 |issue=2 Pt 1 |pages=185–8 |year=1992 |month=Feb |pmid=1739267 |doi= |url=}}</ref>
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| *FNA can also distinguish primary salivary tumor from [[metastatic]] disease
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| *Core needle [[biopsy]] is more accurate compared to [[FNA]] with diagnostic [[accuracy]] greater than 97%<ref>{{cite journal |author=Wan YL, Chan SC, Chen YL, ''et al'' |title=Ultrasonography-guided core-needle biopsy of parotid gland masses |journal=AJNR Am J Neuroradiol |volume=25 |issue=9 |pages=1608–12 |year=2004 |month=Oct |pmid=15502149 |doi= |url=http://www.ajnr.org/cgi/pmidlookup?view=long&pmid=15502149}}</ref>
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| *Findings on [[fine needle aspiration]] (FNA) and core needle biopsy, include:
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| :*Admixture of polygonal epithelial and spindle-shaped myoepithelial elements
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| :*[[Mesenchyme|Mesenchymal stroma]] (important feature)
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| :*Proliferation of [[Myoepithelial cells|myoepithelium]] and [[epithelium]]
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| == Treatment ==
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| === Medical Therapy ===
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| *There is no treatment for pleomorphic adenoma; the mainstay of therapy is surgery.
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| *In some cases, patients with pleomorphic adenoma can receive medications to stimulate saliva production, such as:
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| :*[[Pilocarpine (oral)|Pilocarpine]]
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| :*[[Cevimeline]]
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| === Surgery ===
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| *Surgery is the mainstay of therapy for pleomorphic adenoma.
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| *Surgical excision in conjunction with pre-surgical [[biopsy]] is the most common approach to the treatment of pleomorphic adenoma.
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| *The recurrence rate after surgery will depend on the histological subtype.
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| *Mixed pleomorphic adenomas have a higher recurrence rate.
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| === Prevention ===
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| *There are no primary preventive measures available for pleomorphic adenoma.
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| *Once diagnosed and successfully treated, patients with pleomorphic adenoma are followed-up every 6 or 12 months.
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| ==References==
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| {{Reflist|2}}
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| [[Category:Disease]]
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| [[Category:Oral pathology]]
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| [[Category:Oncology]]
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| [[Category:FinalQCRequired]]
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| {{WH}}
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| {{WS}}
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