Epithelial-myoepithelial carcinoma of the minor salivary glands: immunohistochemical and morphological features.
OBJECTIVE
Epithelial-myoepithelial carcinoma (EMC) is a rare malignant salivary gland neoplasm that most commonly occurs in the parotid gland, but can also arise in the minor salivary glands. Three cases are reported of epithelial-myoepithelial carcinoma of the minor salivary glands, with the goal of better defining this entity.


METHODS
All three cases showed a characteristic nodular/multinodular growth pattern and classic biphasic tubular histology. All parts of each tumor were surrounded by a myoepithelial cell rim and there was evidence of invasion.


RESULTS
Immunohistochemical analysis showed the tumor cells to be weakly positive for S100, cytokeratin (CK) CK5/6, CK7, CKAE-1/AE-3 and strongly positive for epithelial membrane antigen (EMA) and p63; they were focally positive for calponin and acute lymphoblastic leukemia antigen (CD10). The tumor cells were negative for vimentin, alpha-smooth muscle actin (SMA) (except one case), glial fibrillar acid protein (GFAP) and MIB1. The tumors were resected completely with wide margins and no recurrence or metastasis had occurred from 6 to 15 months after surgery.


CONCLUSIONS
Three cases of minor salivary gland tumors are described and the differential diagnosis underlined in relation to benign myoepithelioma. The characteristic morphological and immunohistochemical features aided diagnosis of these biphasic tumors.
Angiero
Francesca
F
Anatomia Patologica, Ospedale San Gerardo Via Pergolesi 33, Monza, Italy. f.angiero@teos.it
Sozzi
Davide
D
Seramondi
Rossella
R
Valente
Maria Gabriella
MG
D000368:Aged; D000369:Aged, 80 and over; D004847:Epithelial Cells / Q000473:pathology; D005260:Female; D006801:Humans; D007150:Immunohistochemistry; D016130:Immunophenotyping; D007633:Keratins / Q000096:biosynthesis; D008297:Male; D008875:Middle Aged; D009208:Myoepithelioma / Q000378:metabolism / Q000473:pathology*; D012468:Salivary Gland Neoplasms / Q000378:metabolism / Q000473:pathology*
D007633:Keratins