Epithelial-myoepithelial carcinoma of the parotid gland: a case report and review of the cytological and histological features

Abstract

Epithelial-myoepithelial carcinoma (EMC) is a rare biphasic tumour of the salivary glands typically arising in the parotid. Fine needle aspiration cytology is widely used in the initial investigation of salivary gland swellings and whilst the cytological features of this tumour have been described they are not well recognized. This report describes the clinicopathological features of a case of epithelial-myoepithelial carcinoma of the parotid gland and highlights the importance of awareness of this tumour in the differential diagnosis of biphasic tumours on fine needle aspiration cytology.

Fine‐needle aspiration cytological findings in five cases of epithelial‐myoepithelial carcinoma of salivary glands

“…4 The cytological features are less well known. Most case reports are of single cases, [5][6][7][8][9][10][11][12] and only three are multicase studies. [13][14][15] Although most cases were reported as malignant or suspicious of malignancy by fine-needle aspiration (FNA), a type-specific diagnosis was not often made and false negative reports have occurred.…”

An unusual presentation of aggressive epithelial-myoepithelial carcinoma of the nasal cavity with high-grade histology

“…14 However, the tumour has been reported to recur locally in the salivary glands following adequate excision, and adjuvant radiotherapy has been used to prevent local recurrence. [15][16][17] However, it is not clear whether radiotherapy is effective, because too few cases have been reported to enable adequate statistical analysis. Furthermore, the effect of chemotherapy on this neoplasm is uncertain.…”

Epithelial Myoepithelial Carcinoma of the Parotid Gland with Malignant Ductal and Myoepithelial Components Arising in a Pleomorphic Adenoma

“…Several other types of salivary gland neoplasms also are composed of both ductal and myoepithelial cells, including PA (mixed tumor) and adenoid cystic carcinoma. [3][4][5]12,16 PA is the most common neoplasm. Resection of the tumor with a safety margin is the treatment of choice, and recurrence, if it occurs, usually does so > 5 years after surgery.…”

“…5,12 The appearances of epithelial myoepithelial carcinoma (EMC) in fine needle aspiration cytology (FNAC) specimens has been described; almost all arose de novo and had benign-appearing epithelial and myoepithelial components. [1][2][3][4][6][7][8][9][10][11][12][13] This is the first cytologic report of this rare tumor with malignant epithelial and myoepithelial cells arising from a PA of the parotid gland.…”

“…The presence of both multilayered clusters of cells and cellular clusters in matrix (amorphous background material) has been reported in some cases of EMC, 2,4,6,9,15,18 but these findings, along with dispersed single cells and naked nuclei, are common to several salivary gland tumors. Trabecular epithelial tissue fragments with a fibrovascular stromal core (pseudopapillary structures) are seen also in other tumors, particularly in low grade polymorphous adenocarcinoma (LGPA).…”