Abstract
Myoepithelial carcinoma (MEC) was first treated as a separate tumor by the World Health Organization (WHO) in 1991. MEC is a rare malignant salivary gland tumor with a reported incidence of 0.2〜0.5% of all salivary gland tumors. We report a case of MEC ex pleomorphic adenoma of a parotid gland in a 75-year-old female with a review of the literature. The patient was referred to our hospital for further evaluation of her right parotid gland tumor. Surgical dissection was performed. Histopathologically, the tumor was composed of a pleomorphic adenoma; there was a rupture of the fibrous capsule and tumor cells had slightly invaded the surrounding tissues.
Immunohistochemical staining showed positive for S-100 protein, α-SMA (smooth muscle actin), and GFAP (glial fibrillary acidic protein).
The postoperative histopathologic examination confirmed the diagnosis of MEC ex pleomorphic adenoma.
For 2 years and 9 months post-operatively, there was no evidence of local recurrence or distant metastasis. We should follow-up carefully.
