|Year : 2016 | Volume
| Issue : 3 | Page : 329-333
Pleomorphic adenoma of the palate: A case report and review of a rare entity
Kamala Rawson1, Basavaraj N Kallalli2, Kalpana Gokul3, Ankur Singh4
1 Department of Oral Medicine and Radiology, Rama Dental College, Kanpur, Uttar Pradesh, India
2 Department of Oral Medicine and Radiology, Hazaribag College of Dental Sciences, Hazaribag, Jharkhand, India
3 Department of Periodontics, Buraydah College of Pharmacy and Dentistry, Buraydah, Saudi Arabia
4 Department of Oral Medicine and Radiology, Narsinhbhai Patel Dental College and Hospital, Visnagar, Gujarat, India
|Date of Submission||28-Sep-2015|
|Date of Acceptance||02-Dec-2016|
|Date of Web Publication||13-Dec-2016|
Dr. Kamala Rawson
Department of Oral Medicine and Radiology, Rama Dental College, Lakhanpur, Kalyanpur, Kanpur - 208 024, Uttar Pradesh
Source of Support: None, Conflict of Interest: None
| Abstract|| |
Pleomorphic adenoma (PA) is the most common benign mixed salivary gland neoplasm that accounts for 60% of all benign salivary gland tumors. It has a diverse histological presentation and occurs in both major and minor salivary glands. PA of minor salivary gland in the palate is a common entity. We report the case of a 40-year-old female who presented with a painless, slow growing swelling of the palate over the last 2 years. Computed tomography (CT) scan revealed an isodense structure in the palate. CT scan showed no signs of bony erosion of the palatal region. Incisional biopsy report revealed PA of the palate. The entire tumor mass was excised along with the overlying mucosa. Histopathological examination confirmed the diagnosis of PA of minor salivary gland. There has been no recurrence of the lesion since 1 year.
Keywords: Adenoma, biopsy, computed tomography, mixed salivary gland tumor, pleomorphic adenoma
|How to cite this article:|
Rawson K, Kallalli BN, Gokul K, Singh A. Pleomorphic adenoma of the palate: A case report and review of a rare entity. J Indian Acad Oral Med Radiol 2016;28:329-33
|How to cite this URL:|
Rawson K, Kallalli BN, Gokul K, Singh A. Pleomorphic adenoma of the palate: A case report and review of a rare entity. J Indian Acad Oral Med Radiol [serial online] 2016 [cited 2022 Nov 26];28:329-33. Available from: http://www.jiaomr.in/text.asp?2016/28/3/329/195655
| Introduction|| |
Pleomorphic adenoma (PA) is the most mundane tumor (60%) of major and minor salivary glands; approximately 70% of the tumors of minor salivary glands are PAs, and the most prevalent intraoral site is the palate, followed by upper lip, buccal mucosa, etc. Studies have reported that, globally, 13.9–51.4% of all salivary gland tumors arise from an intraoral site and 34.7–67.1% of them are benign in nature. This is a tumor of diverse histological and topographical presentation. With several differential diagnoses, the atypical presentations of this tumor are not unconventional. They are more liable to be malignant when associated with minor salivary glands (50%). A benign tumor, though, has the potential to procure a voluminous size, and is generally a symptom-free mass. Fine needle aspiration cytology (FNAC) is a sensitive and concrete diagnostic method implemented for determining astringency of the neoplasm as well as to identify the histological subtype. The aim of this case report is to present histopathologically diagnosed PA of the palate in a 40-year-old female and to emphasize its peculiar nature of growing slowly for over 2 years to a size of 4 × 3 cm, and yet remain asymptomatic. It can be misdiagnosed as a malignant tumor on blind clinical diagnosis, hence, this article emphasizes the need for awareness of its diverse presentation by the examining clinician, that could significantly influence the outcome, and for the histopathological diagnosis of such growth before any definitive treatment.
| Case Report|| |
A 40-year-old female patient visited the Department of Oral Medicine and Radiology with a chief complaint of a slow growing swelling of approximately 2 years duration involving her entire palate, which was peanut sized when she first observed the lesion. The lesion was always asymptomatic, with no associated pain or paresthesia. The patient's medical history was noncontributory. She had no known allergies and had not undergone any surgeries of the head and neck. She had no complaints of pharyngeal or airway obstruction. General physical examination revealed a well-oriented and moderately built individual with no signs of any systemic illness. The patient presented a typical “hot potato in mouth” speech.
The clinical examination revealed a dome-shaped swelling on the palate crossing the midline [Figure 1]. The swelling measured 5 cm × 5 cm in size. The mass had a bosselated surface and the overlying mucosa was pale with pinpoint erythema in the center. The lesion was slightly lobulated, soft to firm, and nontender to palpation [Figure 2]. On the basis of history and clinical examination, a provisional diagnosis of adenoma of the palate was given. The differential diagnosis included median palatal cyst, adenoid cystic carcinoma, mucoepidermoid carcinoma, lymphoma, and myoepithelioma. The patient was further subjected to routine blood and radiographic investigations including occlusal radiograph [Figure 3]. Computed tomography (CT) scan revealed an isodense structure in the palate. CT scan showed no signs of bony erosion of the palatal region [Figure 4] and [Figure 5]. Incisional biopsy was performed, and the specimen was submitted for histopathological investigation, which revealed a PA. Treatment was done with surgical excision of the swelling, which was also sent for histopathological examination, which confirmed it as PA of the palate.
|Figure 4: Computed tomography scan showing the sagittal view with an isodense structure in the palate|
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|Figure 5: Computed tomography scan showing the coronal view with an isodense structure in the palate|
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The photomicrograph revealed parakeratinized stratified squamous epithelium along with connective tissue. The underlying connective tissue showed well-encapsulated mass of sheets and islands of myoepithelial cells and very few duct-like spaces filled with eosinophilic material. Islands of myoepithelial cells were surrounded by eosinophilic myxoid material. There was presence of fibrous area in and around the myoepithelial cells. Salivary gland acini and normal ductal structures were seen in the deeper planes of the sections [Figure 6] and [Figure 7]. The patient was followed up for 6 months, and no sign of recurrence of the disease was noted [Figure 8].
|Figure 7: Photomicrograph showing epithelial and myoepithelial elements arranged in a variety of patterns and embedded in a mucopolysaccharide stroma|
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| Discussion|| |
PA is the most mundane tumor of salivary glands, occurring most commonly in the major salivary glands (84% in the parotid, 8% in the submandibular), and only 4–6% occur in the minor salivary glands., Wang et al. conducted a retrospective study on 737 patients with minor salivary gland tumors in Chinese population. They reported that the incidence of PA (81.8%) was the highest among the benign salivary gland tumors. “Pleomorphic” means a mixed tumor that contains both the types of tissues, epithelial as well as mesenchymal, which begins embryonically. It has been postulated that these tumors arise from intercalated and myoepithelial cells.
Females are more affected than males, with a proportion of 2:1. The reported case is a female. It takes place in the fourth and fifth decades of life, but may occur at any age. The age of the patient in the case reported here was 40 years, which was in accordance with literature. Intraoral PA appears as a gradually growing, painless mass, conventionally in the ages of 40 or 50 years. Tenderness, pain, and ulceration are eccentric. The case presented in this report also had a swelling which grew gradually and was asymptomatic. The most common site of occurance of this tumor is the palatal area (approximately 73%); followed by the upper lip, buccal mucosa, floor of the mouth, tongue, etc., Fewer cases of PA arising in the parapharyngeal space have been reported in literature. The case reported here also presented with a palatal swelling. PA occurring in lips and buccal mucosa is movable in contrast to the ones occurring in the palate.
PA of the palate seldom grows to a size more than 1–2 cm in diameter because it causes arduousness in mastication, speech and deglutition. It is diagnosed and treated earlier than those involving major salivary glands. Our case presented with a swelling larger than 2 cm, this could be due the fact that the patient tolerated the compromise in the function of speech far longer to allow the tumor to grow to the present size. Although it is a benign tumor, it has a high recurrence rate, and in rare cases, a benign PA may transform into a malignant tumor. It lacks a well-defined fibrous capsule, which is a feature associated with high recurrence rate. These tumors are capable of invasion and erosion of the adjacent bone, thus, causing radiolucent mottling on the radiograph of the maxilla. Although the tumor is capable of invasion, it did not show any bone involvement on conventional radiographs. Sharma et al. reported a case of PA of the palate with a duration of 1 year, which was asymptomatic, measuring 2 × 2 cm 2. The mass had a slow growth, was firm in consistency, and had a smooth surface.
The diagnosis of PA is established on the substructure of history, physical examination and cytological and histopathological examinations. Histopathological sampling procedures commonly include FNAC and core needle biopsy (thicker needle used when compared to FNAC). Feinmesser and Gay reported 90% accuracy of FNAC, whereas Clauser et al. reported 97% accuracy of core needle biopsy in determining the malignant nature of a lesion.,
CT scan is of paramount importance in the diagnosis of these tumors as it allows to determine the extension of PA. Although PA does not invade bone, it may lead to resorption of bone due to pressure effect., Daryani et al. reported a case of PA of the palate. CT was performed, which greatly aided in the diagnosis and surgical treatment by revealing a well-circumscribed hypodense mass. In the case reported here, the CT scan helped in confirming that the underlying bone was not involved by the tumor mass, and it also showed the intraoral mass as isodense.
Daryani et al. reported a case of PA of the palate, in which they made the following differential diagnosis: Hematoma (bluish discoloration), mucocele, necrotizing sialometaplasia, mucoepidermoid carcinoma, adenoid cystic carcinoma and polymorphous low grade adenocarcinoma. Sharma et al. also reported a similar swelling where the differential diagnosis was neuroma, palatal abscess, and neurofibroma.
Histopathologically, it is an epithelial tumor of intricate morphology, possessing epithelial and myoepithelial elements arranged in a variety of patterns and embedded in a mucopolysaccharide stroma. The circumventing salivary parenchyma becomes fibrosed and leads to the formation of the capsule. This fibrosed parenchyma is composed of the tumor and is referred to as an erroneous capsule. Similar findings were observed in the present case wherein the underlying connective tissue was showing well-encapsulated mass of sheets and islands of myoepithelial cells, and there was presence of fibrous area in and around the myoepithelial cells.
Conventionally, the tumors of the hard palate are excised through the mucoperiosteum, with 1 cm clinical margins at the periphery. Excision of the palatal bone is not required because periosteum is an efficacious anatomical barrier. If the tumor extends to the soft palate, the excision should include the fascia over the muscles of the soft palate. Usually, pleomorphic adenoma does not recur after adequate surgical excision.
| Conclusion|| |
From the present case report and review of literature, it was concluded that PAs constitute a major part of the benign tumors of the salivary glands. Although it commonly presents in the palate, it rarely exceeds 2 cm in size. The presented case was unique in the size of the tumor, which exceeded due to the delay in reporting. PA could only be diagnosed with the help of biopsy and histopathological investigation. The tumor is encapsulated and is treated with surgical excision including an adequate margin of the normal surrounding tissue. Taking into consideration the recurrence rates reported in literature, it will be wise to have a long follow up.
Declaration of patient consent
The authors certify that they have obtained all appropriate patient consent forms. In the form the patient(s) has/have given his/her/their consent for his/her/their images and other clinical information to be reported in the journal. The patients understand that their names and initials will not be published and due efforts will be made to conceal their identity, but anonymity cannot be guaranteed.
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Conflicts of interest
There are no conflicts of interest.
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[Figure 1], [Figure 2], [Figure 3], [Figure 4], [Figure 5], [Figure 6], [Figure 7], [Figure 8]