Cytology of Plasmacytoid Type Myoepithelioma - Report of Two Cases -

Fine needle aspiration cytology of benign salivary gland tumors with myoepithelial cell participation: an institutional experience of 575 cases

OBJECTIVE

The aim of this study was to evaluate the diagnostic accuracy of fine needle aspiration (FNA) cytology of benign salivary gland tumors with myoepithelial cell participation, namely, pleomorphic adenoma, basal cell adenoma and myoepithelioma, at a single institution over a period of 10 years.

STUDY DESIGN

This study was based on 575 cytologic and matching histological samples (534 pleomorphic adenomas, 26 basal cell adenomas and 15 myoepitheliomas).

RESULTS

In most cases (393/534) of pleomorphic adenoma, a precise diagnosis was given. However, only 2 cases of basal cell adenoma and 1 case of myoepithelioma were diagnosed definitively. Descriptive diagnosis, instead of a definite diagnosis, was rendered in 16.9% of pleomorphic adenomas, 53.8% of basal cell adenomas and 40.0% of myoepitheliomas. Among all cases, the possibility of malignancy was raised in 5.2% of pleomorphic adenomas, 15.4% of basal cell adenomas and 20.0% of myoepitheliomas with a variable degree of suspicion.

CONCLUSION

In some cases, the distinction between these three neoplasms remains difficult in that all exhibit some degree of myoepithelial participation. However, FNA showed a high diagnostic accuracy in diagnosing benign salivary tumors with myoepithelial differentiation, and triage into this category provides sufficient information for clinicians to make treatment decisions.

Imprint cytology of soft tissue myoepithelioma: a case study

Soft tissue myoepithelioma is a rare neoplasm composed of myoepithelial cells. Here, we describe the cytologic features of soft tissue myoepithelioma arising on the right forearm in an 18-year-old man. The excised tumor (3.0×1.8×1.5 cm) was well-demarcated, yellow-gray, soft, and myxoid. The cytologic smears showed round to spindle, epithelioid, and plasmacytoid cells in the myxoid background. The nuclei were uniform, round to ovoid, with finely distributed chromatin and eosinophilic or pale cytoplasm. The tumor cells demonstrated immunoreactivity for cytokeratin (AE1/AE3), epithelial membrane antigen, S100 protein, and glial fibrillary acidic protein. Electron microscopy showed intermediate filaments, desmosomes, and basal lamina.

Plasmacytoid myoepithelioma of the palate: case report

Myoepitheliomas are extremely rare benign neoplasms of salivary glands. They represent 1-1.5% of all salivary gland tumors. They occur, principally, in the parotid gland and infrequently in minor salivary glands. There are distinct histological and immunohistochemical characteristics of the tumor which aid in the diagnosis. Myoepithelioma of the palate is uncommon and only a limited number of cases has been reported in the English literature. Herein, a case of plasmacytoid type of myoepithelioma of the palate in an adult female is presented along with review of the literature.