title: Myoepithelial Carcinoma of the Salivary Glands: A Clinicopathologic Study of 29 Patients.
abstract: OBJECTIVE
  Myoepithelial carcinomas (MECs) of the salivary glands are relatively rare. The clinicopathologic features, immunohistochemical profile, and biologic behavior have not been well-defined.
  
  
  METHODS
  A total of 29 patients with MEC diagnosed during a 10-year period were included in the present study focusing on the biologic behavior, and the pathologic samples of 28 patients were collected for additional investigation of the histologic characteristics. Thirteen samples with detailed immunohistochemical results were included for illustrating immunohistochemical profiles.
  
  
  RESULTS
  The parotid gland (n = 7) was the most common site involved, followed by the palate (n = 6) and the submandibular gland (n = 6). A multinodular growth pattern (n = 14) and sheet-like arrangement of tumor cells (n = 14) were observed. Of the 28 MEC samples, 14 (50%) were epithelioid, 5 (18%) were clear cell, 5 (18%) were plasmacytoid, 3 (11%) were mixed cell type, and 1 (3%) was spindle. The tumor-associated matrix was more prevalently hyalinized than myxoid. Of the 28 cases, 12 (43%) were classified as high grade and 16 (57%) as low grade. Immunohistochemical analysis revealed pan-cytokeratin (92.3%), smooth muscle actin (36%), S-100 protein (54.5%), and p63 (91.7%) positivity and carcinoembryonic antigen (100%) negativity. Ki-67 was immunoreactive in 62% of the MECs, with the Ki-67 labeling index ranging from less than 5 to 20%. Eleven patients developed recurrence (median disease-free survival 43 months) and 11 (44%) developed metastases. Two patients (8%) died of disease after a mean period of 18 months. Fourteen patients (61%) were without any evidence of disease after a mean of 32.5 months (range 3 to 86). The mitotic rate correlated weakly (P = .042) with a poor outcome, but none of the other factors showed a significant correlation with the prognosis.
  
  
  CONCLUSIONS
  MECs of the salivary glands have a relatively high recurrence rate and metastasis rate and a long period of survival with tumor. A combination of pathologic features and various immunohistochemical indexes are crucial for the accurate diagnosis of MECs. Extensive excision is the favorable choice for treating MECs, and suprahyoid lymph node dissection is recommended when the submandibular gland is involved.
authors.affiliation: Department of Oncology, West China College of Stomatology, Sichuan University, Sichuan, People's Republic of China.
authors.forename: Chenxing
authors.initials: C
authors.lastname: Wang
authors.affiliation: Department of Oncology, West China College of Stomatology, Sichuan University, Sichuan, People's Republic of China.
authors.forename: Zhuoyuan
authors.initials: Z
authors.lastname: Zhang
authors.affiliation: Department of Oral and Maxillofacial Surgery, West China College of Stomatology, Sichuan University, Sichuan, People's Republic of China.
authors.forename: Yaneng
authors.initials: Y
authors.lastname: Ge
authors.affiliation: Department of Oncology, West China College of Stomatology, Sichuan University, Sichuan, People's Republic of China.
authors.forename: Zhe
authors.initials: Z
authors.lastname: Liu
authors.affiliation: Department of Oncology, West China College of Stomatology, Sichuan University, Sichuan, People's Republic of China.
authors.forename: Jun
authors.initials: J
authors.lastname: Sun
authors.affiliation: Department of Oncology, West China College of Stomatology, Sichuan University, Sichuan, People's Republic of China.
authors.forename: Zhenjie
authors.initials: Z
authors.lastname: Gao
authors.affiliation: Professor, Department of Oncology, West China College of Stomatology, Sichuan University, Sichuan, People's Republic of China. Electronic address: Lilongjiang_SCU@163.com.
authors.forename: Longjiang
authors.initials: L
authors.lastname: Li
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D009208:Myoepithelioma / Q000235:genetics / Q000473:pathology*; D012468:Salivary Gland Neoplasms / Q000175:diagnosis / Q000473:pathology*; D055815:Young Adult