Myoepithelioma arising from the buccal gland: histopathological and immunohistochemical studies

Intraoral exophytic lesion in an adolescent: A case report of myoepithelioma with unique clinical presentation

Myoepithelioma is an infrequent benign tumor of the salivary glands, characterized by its composition of myoepithelial cells which can show different shapes and be arranged in various patterns with a well-circumscribed or encapsulated growth. This tumor commonly presents in adults as an asymptomatic swelling of the parotid gland, very rarely in minor salivary glands of children or adolescents, and even rarer in the buccal mucosa, with only six cases reported to date and only one of them presented in an adolescent. We present an additional case of myoepithelioma in the buccal mucosa of a 16-year-old male, with a novel clinical presentation as a non-submucosal exophytic mass. Immunohistochemically, neoplastic cells were positive for CK, S100, p63, and GFAP. The tumour was treated surgically, and the patient showed satisfactory evolution at 1 year of follow-up. The clinical and histopathological characteristics of the reported cases are discussed.

Heterogeneity of glandular cells in the human salivary glands: an immunohistochemical study using elderly adult and fetal specimens

Using immunohistochemical staining for alpha-smooth muscle actin (α-SMA), glial fibrillary acidic protein (GFAP), S100 protein (S100), p63, cytokeratin 14 (CK14), and cytokeratin 19 (CK19), we studied acinar and myoepithelial cells of major and minor salivary glands obtained from 14 donated cadavers (78-92 years old) and 5 donated fetuses (aborted at 15-16 weeks of gestation). CK and p63 expression was investigated only in the adult specimens. SMA was detected in all adult glands as well as in fetal sublingual and pharyngeal glands. GFAP expression was seen in a limited number of cells in adult glands, but was highly expressed in fetal pharyngeal glands. S100-positive myoepithelial-like cells were present in adult minor glands as well as in fetal sublingual and pharyngeal glands. Expression of p63 was evident in the ducts of adult glands. CK14 immunoreactivity was observed in a limited number of glandular cells in adults, in contrast to consistent expression of CK19. In both adults and fetuses, a mosaic expression pattern was usually evident for each of the examined proteins. A difference in immunoreactivity for the nerve markers GFAP and S100 was observed between the major and minor glands. Thus, in the present histologic study, we distinguished between the specific gland types on the basis of their immunohistochemical staining. A mosaic expression pattern suggested that the immunoreactivity against nerve protein markers in myoepithelial cells could not be due to the persistence of neural crest remnants or the physiological status of the gland, such as age-related degeneration.

Plasmacytoid myoepithelioma of minor salivary glands: report of case with emphasis in the immunohistochemical findings

Myoepithelioma is a rare benign tumor of the salivary glands and is usually seen in the parotid gland and the minor salivary glands. It was once considered to be a type of pleomorphic adenoma (PA), but myoepitheliomas are today believed to be relatively aggressive tumors. Myoepitheliomas are most common in young adults between the ages of 30 and 50 and there are very few cases reported in individuals less than 18 years of age. We report a case of myoepithelioma located in the hard palate in a 15-year-old Brazilian male. The tumor was composed of plasmacytoid myoepithelial cells. An analysis of the immunohistochemical profile of the tumor cells showed positivity for vimentin, S-100 protein, and glial fibrillary acidic protein (GFAP), but not for smooth muscle actin (α-SMA) and cytokeratin 14 (CK14). We report this case because of the rarity of this tumor, especially in adolescents. We also discuss the histological parameters of the differential diagnosis of this tumor as well as its immunohistochemical profile.

Cutaneous myoepithelioma with a plexiform pattern of growth: a case report

Cutaneous myoepithelioma, a recently recognized, rare but well-characterized entity, is comprised solely of myoepithelial cells. In this report, we describe a cutaneous myoepithelioma with a plexiform pattern of growth in the scapular region of a 58-year-old woman.

Giant myoepithelioma of the upper lip

Myoepithelioma is a relatively rare form of salivary gland tumor composed entirely of myoepithelial cells. This tumor was formerly considered to be a subtype of pleomorphic adenoma; however, in the latest World Health Organization classification of 1991 it is listed as an independent entity. We report herein an extremely rare case of myoepithelioma of the upper lip. A 78-year-old Japanese female presented with a huge, painless mass on her upper lip. CT and MRI revealed a 50 x 40 mm(2) well-defined ovoid tumor. A benign minor salivary gland tumor was clinically suspected, and the patient underwent complete resection of the tumor under general anesthesia. The surgical defect was immediately reconstructed using an Abbe-Estlander flap. The tumor was histopathologically diagnosed as a benign myoepithelioma of the minor salivary gland. Immunohistochemically, the tumor cells were positive for vimentin, cytokeratins, alpha-smooth muscle actin and S-100 protein, confirming the morphological diagnosis of myoepithelioma. The patient's postoperative clinical course was uneventful, and satisfactory results were obtained both functionally and esthetically. The pathology, clinical manifestations and treatment of myoepithelioma are reviewed.