Journal of Dentistry Indonesia Journal of Dentistry Indonesia
Volume 24
Number 3 December Article 7
12-30-2017
Myoepithelioma of the Palate: A Case Report Myoepithelioma of the Palate: A Case Report
Tetsuro Morikawa
Division of Oral Medicine and Pathology, School of Dentistry, Department Postgraduate Program, Health Sciences University of Hokkaido , Hokkaido, Japan, [email protected]
Durga Paudel
Division of Oral Medicine and Pathology, School of Dentistry, Department Postgraduate Program, Health Sciences University of Hokkaido , Hokkaido, Japan
Aya Onishi
Division of Oral Medicine and Pathology, School of Dentistry, Department Postgraduate Program, Health Sciences University of Hokkaido , Hokkaido, Japan
Daichi Hiraki
Division of Oral Medicine and Pathology, School of Dentistry, Department Postgraduate Program, Health Sciences University of Hokkaido , Hokkaido, Japan
Bhoj Raj Adhikari
Division of Oral Medicine and Pathology, School of Dentistry, Department Postgraduate Program, Health Sciences University of Hokkaido , Hokkaido, Japan
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Recommended Citation
Morikawa, T., Paudel, D., Onishi, A., Hiraki, D., Adhikari, B. R., Neopane, P., Harada, F., Utsunomiya, M., Yoshida, K., Sato, J., Nishimura, M., & Abiko, Y. Myoepithelioma of the Palate: A Case Report. J Dent Indones. 2017;24(3): 104-106
This Case Report is brought to you for free and open access by the Faculty of Dentistry at UI Scholars Hub. It has been accepted for inclusion in Journal of Dentistry Indonesia by an authorized editor of UI Scholars Hub.
Myoepithelioma of the Palate: A Case Report Myoepithelioma of the Palate: A Case Report
Authors Authors
Tetsuro Morikawa, Durga Paudel, Aya Onishi, Daichi Hiraki, Bhoj Raj Adhikari, Puja Neopane, Fumiya Harada, Masafumi Utsunomiya, Koki Yoshida, Jun Sato, Michiko Nishimura, and Yoshihiro Abiko
This case report is available in Journal of Dentistry Indonesia: https://scholarhub.ui.ac.id/jdi/vol24/iss3/7
104 Journal of Dentistry Indonesia 2017, Vol. 24, No.3, 104-106 doi: 10.14693/jdi.v24i3. 1145
CASE REPORT
Myoepithelioma of the Palate: A Case Report
Tetsuro Morikawa
1, Durga Paudel
1, Aya Onishi
1, Daichi Hiraki
1, Bhoj Raj Adhikari
1, Puja Neopane
1, Fumiya Harada
1, Masafumi Utsunomiya
1, Koki Yoshida
2, Jun Sato
2, Michiko Nishimura
2, Yoshihiro Abiko
21Division of Oral Medicine and Pathology, School of Dentistry, Department Postgraduate Program, Health Sciences University of Hokkaido , Hokkaido, Japan
2Division of Oral Medicine and Pathology, School of Dentistry, Faculty staff, Health Sciences University of Hokkaido 1757 Kanazawa, Tobetsu-cho, Ishikari-gun, Hokkaido 061-0293 JAPAN
Correspondence e-mail to: [email protected]
ABSTRACT
Myoepithelioma, a benign tumor, occurs with a frequency of 1.5% among all salivary gland tumors, and it most commonly affects the parotid gland. Nearly the entire epithelium is composed of neoplastic myoepithelial cells exhibiting spindle, plasmacytic, epithelial-like, and clear cells. Case Report: A 52-year-old woman with myoepithelioma of the palate. The patient was referred to our hospital with a chief complaint of swelling on the right side of the palate. Following clinical and intraoral examinations, the tumor was removed under general anesthesia. Viewed microscopically, the tumor was seen to be surrounded by a fibrous membrane, primarily composed of a solid growth of neoplastic myoepithelial cells, virtually surrounding a hyaline-like eosinophilic substance. Immunohistochemical examination revealed strongly-positive reactions by the tumor cells for wide- spectrum cytokeratin (CK wide), vimentin, and S-100 proteins. CK 7, smooth muscle actin (SMA), p63, and glial fibrillary acidic protein (GFAP) gave weakly-positive reactions. Conclusion: Based on the findings, a pathological diagnosis of myoepithelioma was reached.
Keywords: myoepithelioma, palate, salivary gland tumor
How to cite this article: Tetsuro Morikawa, Durga Paudel, Aya Onishi, Daichi Hiraki, Bhoj Raj Adhikari, Puja Neopane, Fumiya Harada, Masafumi Utsunomiya, Koki Yoshida, Jun Sato, Michiko Nishimura, Yoshihiro Abiko.
Myoepithelioma of the palate: a case report. J Dent Indones. 2017;24(3):104-106.
INTRODUCTION
Myoepithelioma is a benign epithelial tumor arising from the salivary gland. It occurs with a frequency of 1.5% among all salivary gland tumors, with a predilection for the parotid gland. Histologically, this tumor is characterized by the proliferation of neoplastic myoepithelial cells exhibiting spindle, plasmacytic, epithelial-like, and clear cells.1 Herein, we present a case of myoepithelioma in the palate, along with a description of the histopathological findings.
CASE REPORT
A 52-year-old woman was referred to our outpatient department with a chief complaint of swelling on the right side of the palate. She had noticed a painless but gradually-growing swelling on the palate approximately eight months earlier. Past medical history revealed that
she had undergone a treatment on the endometrium.
There was no documentation of her medical condition.
An intra-oral clinical examination revealed the presence of a well-circumscribed swelling, measuring 10 mm, on the right side of the palate in the oral cavity.
It was covered by healthy-looking oral mucosa (Figure 1), and felt elastic hard on palpation indicative of a benign tumor. Neither X-ray nor computed tomography (CT) examinations demonstrated any obvious abnormal findings in the bone in the palatal region.
The surgical margin was determined to be at 2 mm surrounding the tumor, which was excised under general anesthesia. Viewed microscopically, a fibrous membrane was seen surrounding the tumor (Fig. 2a).
Histopathologically, a solid growth of spindle cells and plasmacytic cells was determined to be the main component of the membrane, virtually surrounding a hyaline-like eosinophilic substance (Figure 2b). No
nuclear or cytological atypia, features of malignancy, were detected. In addition, no mucous component was detected following staining with periodic acid- Schiff (PAS) and mucicarmine. Immunohistochemical staining was carried out using the following primary antibodies: anti-human wide-spectrum cytokeratin (CK wide; DAKO; 1:4000 dilution), anti-human vimentin (DAKO; 1:50 dilution), anti-human S-100 (DAKO;
1:4000 dilution), anti-human CK 7 (DAKO; 1:50 dilution), anti-smooth muscle actin (SMA) (DAKO;
1:100 dilution), anti-human p63 (DAKO; 1:800 dilution), and anti-human glial fibrillary acidic protein (GFAP) (DAKO; 1:1000 dilution). Immunohistochemical studies revealed strongly-positive reactions by the tumor cells for CK wide (Figure 3a), vimentin (Figure 3b), and S-100 (Figure 3c). Weakly-positive reactions were observed for CK 7 (Figura 3d), SMA, and p63, and staining for GFAP was faintly positive. Taken together, these findings led us to diagnose the tumor as a myoepithelioma.
DISCUSSION
The prevalence of myoepithelioma is 1.5% among all salivary gland tumors, and it most commonly affects the parotid gland.2 Nearly the entire epithelium is
composed of neoplastic myoepithelial cells exhibiting spindle, plasmacytic, epithelial-like, and clear cells.1 Myoepitheliomas arising from parotid and palatal glands generally present with spindle cells and plasmacytic cells, respectively.2,3 In the present case, the tumor consisted of a mix of spindle and plasmacytic cells in the palatal region. Normally, myoepithelial cells demonstrate positive immunoreactions for CK wide, vimentin, S-100, and GFAP, and neoplastic myoepithelial cells show positive staining for SMA and p63.4 The immunohistochemical results in the present case were consistent with those normally seen in neoplastic myoepithelial cells. The differential diagnosis of myoepithelioma from pleomorphic adenoma is often subtle, since the presence of neoplastic myoepithelial cells is a common histological feature of pleomorphic adenoma.5 Pleomorphic adenoma shows myxomatous and/or chondroid stroma, with a mixed appearance however, none of these characteristics was observed in the present case.5,6 The tumors are usually surrounded by an unclear fibrous capsule arising from a minor salivary gland, and are generally linked to malignant transformation.6,7 The myoepithelioma carries a benign prognosis and rarely transforms into malignancy. However, the incidence of malignant transformation may be higher in myoepithelioma than in pleomorphic adenoma, making it crucial to distinguish between the two conditions.6,8
CONCLUSION
In conclusion, this report presents a case of myo- epithelioma in the oral palate, diagnosed based on the histopathological findings.
Figure 1. Intraoral cavity. A well-circumscribed swelling (10 mm in diameter) is present on the right side of the palate
Figure 2. Histochemical examination, using hematoxylin and eosin. (a) The tumor surrounded by a brous capsule;
(b) solid growth of spindle cells and plasmacytic cells, seen as the main component of the brous capsule, virtually surrounding a hyaline-like eosinophilic substance
a b
Figure 3. Immunohistochemical staining of the tumor cells.
(a) CK wide; (b) S-100; (c) Vimentin; (d) CK 7 strongly- positive reactions for CK wide, vimentin, and S-100 were observed in the neoplastic cells. The staining for CK 7 was weakly positive in the cells
106 Journal of Dentistry Indonesia 2017, Vol. 24, No.3, 104-106
CONFLICT OF INTEREST
The authors have no conflicts of interest directly relevant to the content of this article.
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(Received July 30, 2017; October 23, 2017)
