Key words parotid

     1 Clinical data

    Patients, female, 62-year-old farmer, was admitted to hospital in October 2006 because of painless mass of the left parotid area. 1 year ago with a tumor in the left parotid region, painless, slow growth, has not been given special treatment. Admission examination: vital signs were normal, the body vital organs examination were normal. Specialist examination: the left parotid area uplift palpable 3cm × 2cm × 2cm size lumps, ill-quality slide no tenderness, peripheral facial paralysis levy, the neck superficial lymph node enlargement. Auxiliary examination: left parotid tumor puncture cytology Tip: tumor-like glandular epithelial cells and foam cells. Admission diagnosis: left parotid mixed tumor. Anesthesia intubation after admission downlink left superficial parotidectomy and mixed tumor resection, intraoperative see the tumor 3cm × 2cm × 1cm size, nodular, located between the superficial lobe of the deep lobe, encapsulated in qualitative branch of the facial nerve through the mass surface, no obvious adhesions surgery went well. The pathology: gray red irregular organization 3cm × 2cm x 1cm size tumor, no significant envelope, cut gray taupe, quality. Microscopic examination: the tumors were invasive growth typical double sleeve-like structure constituted by the two types of cells, luminal inner cuboidal cells, the lumen outer layer of clear cell tumor cells with mild atypia. Immunohistochemistry: CK, EMA inner layer of glandular epithelium showed a positive reaction; S  100 SMA outer layer of myoepithelial positive reaction. The pathological diagnosis: left parotid gland epithelial  myoepithelial cell carcinoma, as shown in Figure 1 to 3.

    2 Discussion

    Epithelial  myoepithelial carcinoma (Epithelial  Myoepithdial Carcinoma, EMC), also known as the intercalated duct cancer, a rare two-cell type, low-grade malignant salivary gland tumors, the prevalence of only 0.5% of the salivary gland tumors [ 1]. Clinically rare. EMC predilection for the elderly, women slightly more common parotid gland is the most common site [2]. The histopathological visible tumor was composed of glandular epithelial cells of the inner layer and the outer layer of clear myoepithelial cells. Glandular epithelial cells cuboidal or short columnar, eosinophilic cytoplasm red dye, round nuclei located in the central this cell formation duct, the outer layer of myoepithelial cells surrounding the transparent, transparent cytoplasm of the tumor cell nuclei have a certain atypia , mitotic rare. The above two cells constitute typical concentric circles or double tube-like structure, the tumor cells have different degrees envelope infringement. Immunohistochemical staining results are shown cytokeratin, S  100 protein and muscle actin-positive to that epithelial – myoepithelial carcinoma and normal tissue myoepithelial cells and salivary gland myoepithelial tumor has the same characteristics of the immune, containing the same antigen component [3], can be used as identification and other salivary gland tumor markers. Biological behavior of this cancer in the past, most of the literature will be listed as one of the low-grade malignant, but Li Hao et al [4] that are in highly malignant salivary gland epithelial  myoepithelial carcinoma, tumors were invasive growth The boundary is not clear, the local recurrence rate, high blood metastasis and poor prognosis. Myoepithelial carcinoma of salivary gland epithelial  treatment with surgery, the first time the surgery is very critical, should be enough boundary; parotid tumors range, close to the facial nerve or recurrent tumors, often need to sacrifice the facial nerve. In this case between the superficial lobe of the deep lobe parotid tumor is located, the boundary clear facial nerve branches from the mass surface through, there is no obvious adhesions glands superficial lobe line preservation of the facial nerve and tumor resection, and given postoperative adjuvant radiation therapy to achieve clinical cure, and this case is still under follow-up. How to reduce the local recurrence rate, and improve the prognosis of patients with salivary gland epithelial – myoepithelial carcinoma of the hot in recent years.