Myoepithelial carcinoma of the parotid gland metastatic to the kidney: Case report and review of the literature

Parotid Myoepithelial Carcinoma in a Pediatric Patient with Multiple Recurrences: Case Report

Myoepithelial carcinoma of the salivary glands is a rare entity, with scarce amount of case reports in the literature. Due to its infrequency, its diagnosis is usually difficult and uncertain. Although there are reports of locoregional recurrences and distant metastases, its low incidence and varied biological behavior limits the clinical evidence that can be used to predict the prognosis and determine the course of treatment. We present a 23-year-old female patient without past medical history with an initial 1-year history of volume increase in the right parotid region of tumor aspect and painful on palpation. As a malignancy was suspected, a total parotidectomy was performed, reporting in the deep lobe a parotid myoepithelial carcinoma with vascular and neural invasion, negative borders, and 3–9 negative regional nodes. During her 16-year clinical evolution, she presented approximately every 2 years and a total of 9 locoregional recurrences and hepatic metastases, including cervical lymphoid nodules, temporal bone, frontal bone, and temporal fossa. Those recurrences have been treated with coordinated efforts between repeated external radiotherapy, chemotherapy, and multiple surgical resections. Myoepithelial tumors represent only 1.0–1.5% of all salivary gland tumors. The literature reports suggest a high incidence of locoregional recurrences and distant metastases in de novo myoepithelial carcinomas. Due to its rarity, treatment continues to be based on the experience of medical staff.

Malignant myoepithelioma of palate

Malignant myoepithelioma is a rare salivary gland neoplasm, which accounts for less than 2% of all the salivary gland carcinomas. Majority of cases have been reported in parotid, and only 8 cases of involvement of the hard palate have been reported in the literature so far. Hereby, a case of painless, ulcerated palatal mass of 2 years of duration reported. A diagnosis of malignant plasmacytoid myoepithelioma was made with the aid of immunohistochemical analysis, and wide surgical excision was considered keeping in mind the biological behavior of the tumor.

Maspin and MCM2 immunoprofiling in salivary gland carcinomas

BACKGROUND

The pathogenesis of salivary gland carcinomas is very complex and prognostic markers are difficult to find in these carcinomas of which the different subtypes have varying malignant potential. The study was conducted to examine the cellular distribution of maspin and MCM2 in salivary gland carcinomas and their value to predict lymph node metastasis.

MATERIALS AND METHODS

Fifty three paraffin blocks of different lesions (15 muco-epidermoid carcinoma, 14 adenoid cystic carcinoma, 3 epi-myoepithelial carcinoma, 5 salivary duct carcinoma, 5 malignant pleomorphic adenoma, 6 polymorphous low grade adenocarcinoma and 5 acinic cell carcinoma) were prepared for immunohistochemical staining with maspin and MCM2 antibodies. ANOVA and Pearson correlation tests were used for the statistical analysis of the results.

RESULTS

All salivary gland carcinomas express maspin and MCM2 with variable cellular localization. There was a significant difference in the expression of each antibody between mucoepidermoid carcinoma, adenoid cystic carcinoma and polymorphous low grade adenocarcinoma. No association was found between examined markers and lymph node metastasis.

CONCLUSIONS

Salivary gland carcinomas express maspin and MCM2 with variable levels and cellular localization, consisting important markers of biological behavior in these tumors. The level of MCM2 expression can be used in the differential diagnosis of adenoid cystic carcinoma and polymorphous low grade adenocarcinoma. Further study with large sample size is recommended to assess their value in prediction of lymph node metastasis.

Myoepithelial carcinoma of the parotid gland with bilateral thyroid involvement: A case report and review of the literature

A patient was admitted to hospital with enlarged lobes of the thyroid gland with bilateral cervical lymph node involvement, and surgical excision followed. Histological examination of this specimen revealed a lesion that showed myoepithelial cell differentiation. Primary thyroid and skin appendage tumors were excluded based on clinical examination, conventional histology and immunohistochemistry. A tumor of the right parotid surgically treated in June 2008, approximately 2 years previously, was originally classified as a basal cell adenocarcinoma with focal invasion, but was re-examined. Using immunohistochemistry, the parotid tumor was re-classified as a myoepithelial carcinoma. The thyroid tumor proved to be metastasis from a primary parotid tumor, which was not found in the updated review of the literature. The literature is reviewed, including current knowledge on the histological and immunohistochemical features of myoepithelial carcinoma, with limited data on treatment suggestions.