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High‐grade epithelial‐myoepithelial carcinoma of the parotid gland with mucous cell differentiation
Author(s) -
Sentani Kazuhiro,
Ogawa Ikuko,
Uraoka Naohiro,
Ikeda Masayuki,
Hayashi Naoki,
Hattori Takuya,
Hattori Yui,
Oue Naohide,
Takata Takashi,
Yasui Wataru
Publication year - 2015
Publication title -
pathology international
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.73
H-Index - 74
eISSN - 1440-1827
pISSN - 1320-5463
DOI - 10.1111/pin.12315
Subject(s) - myoepithelial cell , pathology , nuclear atypia , atypia , gross examination , salivary gland , hyaline , malignancy , parotid gland , medicine , biology , anatomy , immunohistochemistry
Epithelial‐myoepithelial carcinoma ( EMC ) is a rare salivary gland tumor with a low‐grade malignancy, and EMC with high‐grade histopathological features is exceedingly rare. Furthermore, EMC with intracellular mucin is also extremely rare. We report an uncommon case of a high‐grade EMC of the parotid gland with mucous cell differentiation in a 66‐year old Japanese woman who noticed a right palpable parotid mass increasing in size within a one‐year period. The cytological specimen showed a focally biphasic structure and included isolated or discohesive piled‐up clusters with hyaline globules surrounded by neoplastic cells with nuclear atypia. The gross examination revealed a relatively well‐demarcated, multinodular gray‐whitish and solid mass. Histologically, the tumor consisted of variably sized solid nests or trabeculae with central necrosis and increased mitotic activity, and invaded into adjacent skeletal muscles. Immunohistochemically, the biphasic ductal and myoepithelial differentiation of this tumor confirmed the diagnosis of high‐grade EMC . Furthermore, numerous small nests with d‐ PAS and alcian blue‐positive mucous cells predominated in about 5% of the whole tumor, and these mucous cells were encompassed by neoplastic myoepithelial cells. We should recognize this variant of EMC because we can't rule out the possibility of EMC even in the presence of mucous cells.