Malignant Parotid Gland Tumors: A Retrospective Analysis Of141Cases

Purpose：Malignant parotid gland tumors occupy a certain proportion in oral andmaxillofacial malignant tumors. The diagnosis of malignant parotid gland tumorclinically is difficult. Misdiagnosis and improper treatment can compromise the facialnerve function and the appearance and can be life-threatening as well. This paper,through a retrospective analysis, summarizes the composition of malignant parotidtumors and their clinical characteristics to improve the diagnosis and treatment ofmalignant parotid gland tumors.Methods：Medical records of141patients operated between January2001andDecember2012for malignant parotid tumors in the Department of Oral andMaxillofacial Surgery, the1stAffiliated Hospital of Dalian Medical University wereretrospectively reviewed. The data included incidence, clinical manifestations, imagingfindings, pathological diagnosis, operation methods, etc.Results：72of141cases were men and69of them were women. Male to femaleratio is1.04:1. The median and mean ages were48years and46.5years respectively(range7-86years).44%of the patients were in range of40-59years. The time sincethe patients noticed the tumor to the time they presented to our department ranged from2days to30years.41patients (29%) presented to us within3months while it was3years or more for38patients (27%). Tumor mobility was good in42cases (29.8%),borders were well-defined in89cases (63%), no pain symptoms in92cases (65%), andno invasion into the surrounding tissues by the tumor in45cases (32%). On CTexamination of128cases, borders were ill-defined in64cases (50%), non-uniformdensity in62cases (48%), irregular shape in80cases (63%). The three most commonmalignant parotid tumors were mucoepidermoid carcinoma (25.5%), adenoid cysticcarcinoma (15.6%) and acinar cell carcinoma (14.9%).Conclusion：Mucoepidermoid carcinoma was the most common malignant parotid gland tumor. The tumor progression was relatively long (more than1year) in more thanhalf of the cases. It was rapid in one third of the cases, the most common beingmucoepidermoid carcinoma. Well-defined borders, good tumor mobility, no invasioninto surrounding tissues by the tumor can’t rule out the possibility of malignant parotidtumor. Further examination is essential. The irregular shape of the lump on CT hassome value in the diagnosis of the malignant parotid gland tumor while the tumorborders, uniform density, contrast-enhanced CT are of no obvious help in theidentification of benign and malignant tumors of parotid gland. Fine needle aspirationbiopsy can aid in the identification of benign and malignant tumors of parotid glandpreoperatively with the accuracy of upto86%and thus can have a significant role inguiding the choice of parotid gland tumor surgery. Frozen section biopsy helps in theintraoperative diagnosis with the accuracy of upto93%. It is of great significance indeciding whether the facial nerve is to be sacrificed or preserved. The parotid glandtumor surgery should be selected according to the tumor site, imaging findings, clinicalstaging, and the intraoperative findings, and adapted to fit the frozen section biopsyresults.