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Pleomorphic Adenoma

Chondroid Syringomas

Pleomorphic adenoma is a benign, slow-growing neoplasm that most commonly affects the parotid gland. It has epithelial, myoepithelial, and stromal components. The prognosis is generally good after the surgical removal, however, there is an increased incidence of recurrence particularly if the parotid gland is affected.


Presentation

Pleomorphic adenoma (PA) is the most common type of benign tumor of the salivary gland [1] [2] [3].

Pleomorphic adenoma or benign mixed tumor, occur most frequently (85%) in the parotid glands [2], followed by the minor salivary glands in 10% of the cases, and then by the submandibular glands at 5% [2]. The adenoma presents as a small, mobile, slowly growing, painless mass of 2-6 cm; however, occasionally much larger tumors have been encountered [4]. Patients have varying symptoms, which may depend on the location of the tumor, and may include hoarseness of voice, dyspnea, and difficulty in chewing and eating.

The tumors occur most frequently in middle-aged women. They originate in most cases from the superficial lobe of the parotid gland and present as a swelling of the gland below the ear; however, they can develop in the deep lobe of the parotid gland, where they will not be easily noticed in early stages [5]. Tumors of the deep lobe of the parotid gland, and of the minor salivary glands sometimes appear in the parapharyngeal space [6]. More common locations for adenomas of the minor salivary glands are the hard and soft palate, and the mucosa of the lip [7]. Most tumors are solitary, but bilateral tumors have also been found [5]. The facial nerve is rarely involved.

The adenomas are often encapsulated. The histological pattern varies case by case [3[. All tumors are mixtures of epithelial cells, myoepithelial and basal cells, with varying contributions from stroma; using the relative amounts of different cell types and stroma for predicting future outcomes has not yet met with success [3].

Although PA is a benign tumor, it can become malignant. Surgical removal of the tumor by enucleation –or preferably by parotidectomy at the first incidence [8]- is the cornerstone of treatment. Surgery has to be done carefully to preserve the facial nerve and to avoid rupture, which could lead to recurrence of the tumor.

Pleomorphic adenomas of the lacrimal glands (PALG) constitute about a tenth of the lacrimal gland tumors. Patients with PALG present with slowly progressing proptosis. The treatment for PALG is total removal of the tumor [9].

Parotid Mass
  • A well-defined parotid mass with increased signal intensity on proton density- and T2-weighted images is highly suggestive of the diagnosis.[emedicine.com]
  • We report a case of a 77-year-old man, who presented with a 6-year history of a parotid mass that had undergone rapid growth within weeks.[ncbi.nlm.nih.gov]
  • In our case a 66-year-old male presented with the right parotid mass for 5 years rapidly increasing for the last 3 months.[ncbi.nlm.nih.gov]

Workup

The radiological tools for the diagnosis and differentiation of salivary gland disease are computerized tomography (CT) scans, magnetic resonance imaging (MRI), and ultrasonography [1] [10]. MRI may be the instrument of choice over CT scan, because of its superior definition of soft tissue and tumor margins [2]. Ultrasound may also be used to serve as the first diagnostic tool; it can differentiate malignant lesions from benign ones with very high accuracy (96%), and can successfully predict PA cases [10]. Apart from location, shape, dimensions and margin [10], ultrasound can distinguish between cystic and solid masses, and between intra- and extracapsular tumors [2]. It can also be used for guiding fine needle biopsy [10].

Fine needle aspiration biopsy is also an important tool for preoperative diagnosis; it is safe and reliable but its sensitivity is variable and is more accurate for the diagnosis of benign lesions than for malignant ones [11] [12] [13].

Because of the diverse histological appearance of PAs, it may not be easy to differentiate them histologically from other neoplasms, such as myoepithelioma or some carcinomas [2].

Treatment

  • Much has changed since the topic was reviewed in 2001, and this manuscript comments on clinical progress and discusses patient treatment options. RECENT FINDINGS: Surgery is the preferred treatment for head and neck pleomorphic adenoma.[ncbi.nlm.nih.gov]
  • Knowledge of the recurrence risk factors could allow selection of treatments that minimize the risk.[ncbi.nlm.nih.gov]
  • We examined patients demographics, disease characteristics, treatment, and outcome and as well as the time period length from the first discovery of a recurrent mass until seeking treatment at our clinic and its effect on morbidity.[ncbi.nlm.nih.gov]
  • Carew, JF, Spiro, RH, Singh, B, Treatment of recurrent pleomorphic adenomas of the parotid gland . Otol Head Neck Surg 1999 ; 121: 539 – 42 . Google Scholar SAGE Journals ISI 4. Phillips, PP, Olsen, KD.[doi.org]
  • Surgical excision of the tumor mass forms the mainstay of treatment, with utmost care taken to preserve the facial nerve.[ncbi.nlm.nih.gov]

Prognosis

  • Further accumulation of cases and long follow-up data are needed to elucidate the pathophysiology and prognosis of MEC ex PA.[ncbi.nlm.nih.gov]
  • HER-2-positive tumours conferred short overall survival time (P 0.036) and short disease-specific survival time (P 0.042) in patients, but HER-2 status was not an independent predictor of prognosis.[ncbi.nlm.nih.gov]
  • In the present study, we confirmed the role of PLAGL2 in the prognosis of CRC patients and provide molecular evidence of PLAGL2 promoted EMT in CRC cell line SW480.[ncbi.nlm.nih.gov]
  • Abstract Carcinoma ex pleomorphic adenoma is a rare salivary gland malignancy with a poor prognosis that can metastasize to the lungs. Endobronchial metastasis and associated bronchoscopic characteristics have not been described in the literature.[ncbi.nlm.nih.gov]
  • BACKGROUND: Carcinosarcoma of the salivary glands is a rare neoplasm, and the minimally invasive form constitutes a subgroup with a more favorable prognosis.[ncbi.nlm.nih.gov]

Etiology

  • Salivary Gland Neoplasms/complications Salivary Gland Neoplasms/pathology* Tongue Neoplasms/diagnosis* Tongue Neoplasms/etiology Tongue Neoplasms/pathology Supplementary concept Salivary Gland Adenoma, Pleomorphic[ncbi.nlm.nih.gov]
  • The markedly different Ga-DOTA-TOC avidity suggested a different etiology, and histological examination demonstrated a pleomorphic adenoma.[ncbi.nlm.nih.gov]
  • Morton, Piero Nicolai, Vincent Vander Poorten and Peter Zbären , Etiology and management of recurrent parotid pleomorphic adenoma , The Laryngoscope , 125 , 4 , (888-893) , (2014) .[doi.org]
  • The etiology of these tumors remains unknown. Unlike squamous cell carcinoma, for which more than 90% of patients are smokers, only 50% to 60% of patients with minor salivary gland tumors are smokers.[doi.org]
  • The etiology of PA's is unknown, however some authors mention the myoepithelial cell as responsible for the development of this pathology (Ledesma-Montes et al.).[scielo.conicyt.cl]

Epidemiology

  • INTRODUCTION: Whereas salivary gland pleomorphic adenoma (SGPA) is the most common type of salivary gland tumor, little is known about its epidemiology because national cancer registries do not register this disease.[ncbi.nlm.nih.gov]
  • Institud de Diagnòstic per la Imatge (IDI), Bellvitge Hospital, 08907, L'Hospitalet de Llobregat, Barcelona, Spain. 5 Department of Medical Oncology, IDIBELL, Catalan Institute of Oncology (ICO), L'Hospitalet de Llobregat, Barcelona, Spain. 6 Cancer Epidemiology[ncbi.nlm.nih.gov]
  • Epidemiology Mean age of presentation is mid-forties but the tumour can occur at any age after 10. Women are more commonly affected. Most tumours arise in the parotid gland (80%). Natural History The tumour is usually slowly growing.[ozradonc.wikidot.com]
  • The epidemiology of pleomorphic adenoma can cover all ages and both genders but is more prevalent among women from thirty to sixty years of age. From its name, pleomorphic depicts variability in its morphology.[cancerwall.com]
  • Epidemiology Lacrimal gland tumors represent approximately 9% of all orbital masses.[eyewiki.aao.org]
Sex distribution
Age distribution

Pathophysiology

  • Further accumulation of cases and long follow-up data are needed to elucidate the pathophysiology and prognosis of MEC ex PA.[ncbi.nlm.nih.gov]
  • Genetic rearrangements, such as chromosomal translocations involving 8q12 target the PLAG1 gene, may contribute to the pathophysiology of PALG.[eyewiki.aao.org]

Prevention

  • Furthermore, the tumour capsule may not be the only barrier preventing invasion and metastasis, as a significant reduction in numbers of myoepithelial cells correlates with invasion and metastasis in CXPA patients.[ncbi.nlm.nih.gov]
  • Chemotherapy prevented recurrent growth of the lesion and extended survival. The patient was alive with cancer 30 months after the first surgery. CONCLUSIONS: High expression of the Ki67 labeling index might reflect prognosis of these cases.[ncbi.nlm.nih.gov]
  • Treatment of the benign tumor is essential is preventing a malignant tumor from occurring.[healthyliving.azcentral.com]
  • Total parotidectomy is preferred, if possible, to prevent recurrence. Causes The most common causes of all salivary gland issues is the inability of the saliva to properly drain, usually from salivary duct blockages.[healthyliving.azcentral.com]
  • […] metastasis metastases of these benign pleomorphic adenomas are thought to be associated with intraoperative implantation of tumour cells through vascular or lymphatic routes (2) therefore meticulous resection at the initial operation is important to prevent[gpnotebook.co.uk]

References

Article

  1. Rai S, Sodhi SP, Sandhu SV. Pleomorphic adenoma of submandibular gland: An uncommon occurrence. Natl J Maxillofac Surg. 2011 Jan;2(1):66-68.
  2. Jain S, Hasan S, Vyas N, Shah N, Dalal S. Pleomorphic Adenoma of the Parotid Gland: Report of a Case With Review of Literature. Ethiop J Health Sci. 2015 Apr; 25(2): 189–194.
  3. Di Palma S, Simpson RHW, Skalova A, Leivo I. Major and Minor Salivary Glands. In: Cardesa A, Slootweg PJ, eds. Pathology of the head and neck. Berlin:Springer; 2006:131-170.
  4. Guerriere CN, Goff BJ, Cummings GH, Auber AE. An unusually large, solid tumor of the parotid gland. Ann Plast Surg. 1999 Nov;43(5):529-532.
  5. Silva SJ, Costa Junior GT, Brant Filho AC, Faria PR, Loyola AM. Metachronous bilateral pleomorphic adenoma of the parotid gland. Oral Surg Oral Med Oral Pathol Oral Radiol Endod. 2006 Mar;101(3):333-338.
  6. Hakeem AH, Hazarika B, Pradhan SA, Kannan R. Primary pleomorphic adenoma of minor salivary gland in the parapharyngeal space. World J Surg Oncol. 2009 Nov 12;7:85.
  7. Pons Vicente O, Almendros Marqués N, Berini Aytés L, Gay Escoda C. Minor salivary gland tumors: A clinicopathological study of 18 cases. Med Oral Patol Oral Cir Bucal. 2008 Sep 1;13(9):E582-588.
  8. Wittekindt C, Streubel K, Arnold G, Stennert E, Guntinas-Lichius O. Recurrent pleomorphic adenoma of the parotid gland: analysis of 108 consecutive patients. Head Neck. 2007; 29(9):822-828.
  9. Rose GE, Wright JE. Pleomorphic adenoma of the lacrimal gland. Br J Ophthalmol. 1992 Jul;76(7):395-400.
  10. Bialek EJ, Jakubowski W, Karpinska G. Role of ultrasonography in diagnosis and differentiation of pleomorphic adenomas. Arch Otolaryngol. Head Neck Surg. 2003;129:929–933.
  11. Contucci AM, Corina L, Sergi B, Fadda G, Paludetti G. Correlation between fine needle aspiration biopsy and histologic findings in parotid masses. Acta Otorhinolaryngol Ital. 2003 Aug;23(4):314-318.
  12. Sergi B, Contucci AM, Corina L, Paludetti G. Value of fine-needle aspiration cytology of parotid gland masses. Laryngoscope. 2004 Apr;114(4):789.
  13. Akhavan-Moghadam J, Afaaghi M, Maleki AR, Saburi A. Fine Needle Aspiration: An Atraumatic Method to Diagnose Head and Neck Masses. Trauma Mon. 2013 Dec; 18(3): 117–121.

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Last updated: 2018-06-22 04:52