Pleomorphic adenoma
Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1] Associate Editor(s)-in-Chief: Maria Fernanda Villarreal, M.D. [2]
Synonyms and keywords: Pleomorphic adenoma of the salivary glands; BMT; Benign mixed tumors of the salivary gland
Overview
Pleomorphic adenoma (also known as "Benign mixed tumor of the salivary gland") is a benign neoplastic tumor of the salivary glands. Pleomorphic adenoma is the most common type of salivary gland tumor and the most common tumor of the parotid gland.[1]
Historical Perspective
- Pleomorphic adenoma was first discovered by Beahrs in in 1957.
Classification
- Pleomorphic adenoma may be classified according to [classification method] into [number] subtypes/groups:
- [group1]
- [group2]
- [group3]
- Other variants of pleomorphic adenoma include [disease subtype 1], [disease subtype 2], and [disease subtype 3].
Pathophysiology
- The pathogenesis of pleomorphic adenoma is characterized by [feature1], [feature2], and [feature3].
- The [gene name] gene/Mutation in [gene name] has been associated with the development of pleomorphic adenoma, involving the [molecular pathway] pathway.
- On gross pathology, [feature1], [feature2], and [feature3] are characteristic findings of pleomorphic adenoma.
- On microscopic histopathological analysis, [feature1], [feature2], and [feature3] are characteristic findings of pleomorphic adenoma.
Causes
- Common causes of pleomorphic adenoma, include:
Differentiating Pleomorphic Adenoma from Other Diseases
- Pleomorphic adenoma must be differentiated from other diseases that cause [clinical feature 1], [clinical feature 2], and [clinical feature 3], such as:
- [Differential dx1]
- [Differential dx2]
- [Differential dx3]
Epidemiology and Demographics
- The prevalence of pleomorphic adenoma is approximately [number or range] per 100,000 individuals worldwide.
- In [year], the incidence of pleomorphic adenoma was estimated to be [number or range] cases per 100,000 individuals in [location].
Age
- Pleomorphic adenoma is more commonly observed among patients aged [age range] years old.
- Pleomorphic adenoma is more commonly observed among [elderly patients/young patients/children].
Gender
- Pleomorphic adenoma affects men and women equally.
- [Gender 1] are more commonly affected with pleomorphic adenoma than [gender 2].
- The [gender 1] to [Gender 2] ratio is approximately [number > 1] to 1.
Race
- There is no racial predilection for pleomorphic adenoma.
Risk Factors
- Common risk factors in the development of pleomorphic adenoma, include:
Natural History, Complications and Prognosis
- The majority of patients with pleomorphic adenoma remain asymptomatic for [duration/years].
- Early clinical features include [manifestation 1], [manifestation 2], and [manifestation 3].
- If left untreated, the majority of patients with pleomorphic adenoma may progress to develop [manifestation 1], [manifestation 2], and [manifestation 3].
- Common complications of pleomorphic adenoma include [complication 1], [complication 2], and [complication 3].
- Prognosis is generally [excellent/good/poor], and the [1/5/10year mortality/survival rate] of patients with pleomorphic adenoma is approximately [#%].
Diagnosis
Diagnostic Criteria
- The diagnosis of pleomorphic adenoma is made when at least [number] of the following [number] diagnostic criteria are met:
- [criterion 1]
- [criterion 2]
- [criterion 3]
- [criterion 4]
Symptoms
- Pleomorphic adenoma is usually asymptomatic.
- Symptoms of pleomorphic adenoma may include the following:
- [symptom 1]
- [symptom 2]
- [symptom 3]
- [symptom 4]
- [symptom 5]
- [symptom 6]
Physical Examination
- Patients with pleomorphic adenoma usually appear [general appearance].
- Physical examination may be remarkable for:
- [finding 1]
- [finding 2]
- [finding 3]
- [finding 4]
Laboratory Findings
- There are no specific laboratory findings associated with pleomorphic adenoma.
Imaging Findings
- MRI is the imaging modality of choice for pleomorphic adenoma.
- On CT, characteristic findings of pleomorphic adenoma, include:
- Smooth, and well-marginated tumors
- The attenuation values of the mass are usually homogeneous and higher than that of the surrounding gland
- Tumor enhancement is variable and can result in a missed diagnosis if delayed images are not acquired
- Pleomorphic adenomas are poorly enhancing in the early phase of contrast enhancement, though the amount of enhancement increases over time).
- On MRI, characteristic findings of pleomorphic adenoma, include:
- Pleomorphic adenomas are usually well-circumscribed
- Homogeneous masses with low intensity on T1-weighted images and high intensity on T2-weighted images.
- They commonly have a rim of decreased signal intensity on T2-weighted images.
- After gadolinium enhancement, the tumors are homogeneously enhancing unless they are large.
Gallery
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MRI: A right parotid pleomorphic adenoma Images courtesy of RadsWiki
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MRI: A right parotid pleomorphic adenoma Images courtesy of RadsWiki
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MRI: A right parotid pleomorphic adenoma Images courtesy of RadsWiki
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MRI: A right parotid pleomorphic adenoma Images courtesy of RadsWiki
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MRI: A right parotid pleomorphic adenoma Images courtesy of RadsWiki
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PET: A right parotid pleomorphic adenoma Images courtesy of RadsWiki
Other Diagnostic Studies
- Pleomorphic adenoma may also be diagnosed using fine needle aspiration (FNA) and core needle biopsy.
- Findings on fine needle aspiration (FNA) and core needle biopsy, include:
Treatment
Medical Therapy
- There is no treatment for pleomorphic adenoma; the mainstay of therapy is surgery.
- In some cases, patients with pleomorphic adenoma can receive medications to stimulate saliva production, such as:
- Pilocarpine
- Cevimeline
Surgery
- Surgery is the mainstay of therapy for pleomorphic adenoma.
- Surgical excision in conjunction with pre-surgical biopsy is the most common approach to the treatment of pleomorphic adenoma.
Prevention
- There are no primary preventive measures available for pleomorphic adenoma.
- Once diagnosed and successfully treated, patients with pleomorphic adenoma are followed-up every 6 or 12 months.
- Follow-up testing includes [test 1], [test 2], and [test 3].
References
- ↑ Ewa J. Bialek, Wieslaw Jakubowski, Piotr Zajkowski, Kazimierz T. Szopinski, and Antoni Osmolski. US of the Major Salivary Glands: Anatomy and Spatial Relationships, Pathologic Conditions, and Pitfalls. RadioGraphics 2006 26: 745-763.