Histologic variant of the epithelial-myoepithelial carcinoma of the salivary gland: a case report

Epithelial-myoepithelial carcinoma of external auditory canal evolving from pleomorphic adenoma

A 45-year-old female patient visited the clinic due to ear fullness. A 8 mm sized mass was found in the external auditory canal. It was surgically removed and the pathology exam confirmed epithelial-myoepithelial carcinoma (EMC). EMC is glandular epithelial neoplasm of the salivary gland. EMC originating from the external auditory canal is very rare, and only 1 case has been reported so far in the literature. The difference between our case and the one previously published was that the tumor was previously proven as a benign tumor (i.e. pleomorphic adenoma) 5 years ago. Therefore, this is the first case in the literature showing the evolvement of pleomorphic adenoma of the external auditory canal into EMC.

Epithelial-myoepithelial carcinoma: a review of the clinicopathologic spectrum and immunophenotypic characteristics in 61 tumors of the salivary glands and upper aerodigestive tract

To further define the clinicopathologic spectrum of epithelial-myoepithelial carcinoma (EMCa), we report the gross, histologic, and immunophenotypic characteristics of 61 tumors seen within a 30-year-period. The mean age at presentation was 60.9 years, with a female predominance (1.5:1). The most common sites were parotid (62.1%), sinonasal mucoserous glands (10.3%), palate (8.6%), and submandibular (8.6%). Most EMCas showed a characteristic nodular/multinodular growth pattern and classic biphasic tubular histology. However, new morphologies in EMCa such as ancient change (8.2%), "Verocay"-like change (3.3%), and sebaceous differentiation (13.1%) were noted. Specific histologic variants were dedifferentiated EMCa (3.3%), oncocytic EMCa (8.2%), EMCa ex pleomorphic adenoma (1.6%), double-clear EMCa (3.3%), and EMCa with myoepithelial anaplasia (3.3%). All cytokeratin cocktails selectively highlighted the epithelial component well. Of the myoepithelial markers, p63, smooth muscle actin and vimentin performed best. Bcl-2 and c-kit were frequently positive (66.7% and 69.2%, respectively). p53 was highly expressed only in 1 dedifferentiated EMCa. The recurrence rate was 36.3% (median disease-free survival 11.34 y), but death was rare with 5-year and 10-year disease-specific survivals of 93.5% and 81.8%, respectively. The most important univariate predictors of recurrence were margin status (log rank P=0.006), angiolymphatic invasion (P=0.002), tumor necrosis (P=0.004), and myoepithelial anaplasia (P=0.038). Thus, EMCa is generally a low-grade tumor with a broader morphologic spectrum than previously thought, with several key features predictive of recurrence. Immunohistochemistry can aid diagnosis by highlighting the biphasic nature of the tumor.

Malignant myoepithelioma arising from recurrent pleomorphic adenoma of the soft palate

Malignant myoepithelioma is a rare salivary gland neoplasm that can arise either de novo or within a pre-existing pleomorphic adenoma. We report a case of malignant myoepithelioma arising from a pleomorphic adenoma of the soft palate. A 70-year-old woman presented in our department with a very large tumor of the soft palate. The patient had a history of a pleomorphic adenoma at the same location that was surgically removed 2 years ago. A second operation, with intraoral excision of the tumor was performed. Histological examination of the recurrence revealed a malignant spindle cell neoplasm with an infiltrative growth pattern and a high mitotic rate. Immunohistochemical investigation confirmed the diagnosis of a low-grade carcinoma of myoepithelial origin with free surgical margins. The patient remains free of disease for more than twelve months after the end of treatment.

Epithelial-myoepithelial carcinoma of the parotid gland

We report a rare case of epithelial-myoepithelial carcinoma (EMC) of the parotid gland. A 70-year-old man presented with a 4-months-history of right-sided subauricular swelling. Computed tomographic scans revealed a well-defined mass with cystic lesion, measuring about 40 mm in diameter, in the right parotid gland. Because the tumor occupied superficial lobe, he underwent superficial parotidectomy with preservation of the facial nerve. On the basis of the histological and immunohistochemical findings, the tumor was diagnosed as EMC. His post-operative course was uneventful, and he is currently free from disease 6 months after surgery. Diagnosis, clinical behavior and treatment of EMC are reviewed from perusal of the literature.

Epithelial-myoepithelial carcinoma arising in the nasal cavity: a case report and review of literature

Epithelial-myoepithelial carcinoma is an uncommon, low-grade, malignant epithelial neoplasm composed of variable proportions of ductular cells and large, clear staining, myoepithelial cells arranged around the periphery of the ducts. About 120 cases have been reported in the world literature, most of which were located in salivary glands, except for a few cases occurring in unusual locations such as breast, lacrimal gland, nose, paranasal sinus, trachea, bronchus, and lung. We here reported the second case of epithelial-myoepithelial carcinoma of the nasal cavity with extension to the nasopharynx. The patient was a 61 year old Chinese female with two month's history of progressive nasal obstruction. Histopathologically, the tumor showed typical myoepithelial and ductal cells biphasic differentiation, duct-like structure and infiltrating growth pattern. Some ductal cells showed the characteristics of oxyphilic cell, which had never been reported before. Recurrence and metastasis rates of epithelial-myoepithelial carcinoma varied from 35% to 50% and 8.1% to 25% respectively in different reports. The present case had neither recurrence nor metastasis twenty months after operation. When epithelial-myoepithelial carcinoma is mainly composed of spindle myoepithelial cells, the differential diagnosis should include myoepithelioma, neurofibroma, leiomyoma and hemangiopericytoma.

Epithelial-myoepithelial carcinoma of the salivary gland--a low grade malignant neoplasm? Report of two cases and review of the literature

Epithelial-myoepithelial carcinomas (EMC) are rare neoplasms of the salivary gland with an incidence of less than 1% arising predominantly in the parotid gland. Although they are thought to be of low grade malignancy, fatal courses are described. We report a case of EMC of the parotid gland in a 58-year-old woman with an unfavorable course of this disease in long term follow-up. The malignant potential of this tumor is discussed. In addition, we include another case of EMC of the submandibular gland.

Lymphoepithelial carcinoma of salivary glands

BACKGROUND

Malignant lymphoepithelial lesions (MLEL) or lymphoepithelial carcinoma or undifferentiated carcinoma with lymphoid stroma, is a rare but unique malignancy of the major salivary glands. There is an exceptionally high incidence in Eskimos and native Greenlanders, but it has never been reported in the Arab population. We report the first case from Saudi Arabia in the native Arabs. These are unencapsulated tumors with a strong tendency to metastasize to the regional lymph nodes.

METHODS

We reviewed English and Arabic literature and found the total number of reported cases of MLEL to be 103 with predominant involvement of the parotid gland. Parotidectomy followed by neck dissection and radiotherapy was performed, with a survey of the nasopharynx and EB virus titer.

RESULTS

The patient underwent radical neck dissection followed by radiation after developing the neck metastasize. Three years to date he remains in remission with no distant or regional metastases.

CONCLUSION

Malignant lymphoepithelial lesions of the salivary gland are unencapsulated tumors with poorly differentiated epithelial cells scattered throughout fibrolymphocytic stroma. They have a strong tendency to metastasize to the regional lymph nodes with predominant involvement of the parotid gland. They are commonly associated with Epstein-Barr virus infection. The majority of them are radiosensitive. Combination therapy with surgery and radiation is desirable to control the disease. We recommend complete surgical excision with neck dissection followed by postoperative radiotherapy to the local site as well as to the neck as treatment of choice.