Malignant tumors of the parapharyngeal space

Most parapharyngeal space tumors are benign, and malignancies are rare. We report the results of a retrospective review of patients with primary parapharyngeal space malignant tumors treated at our institution from 1994 to 2007. During this period, 42 patients seen at our institution were found to have parapharyngeal space tumors. Six tumors (14.3%) were malignant and 36 (85.7%) were benign. Six of 21 (28.6%) prestyloid tumors were malignant, and malignant tumors were all found in the prestyloid region in MRI. There were three carcinoma ex pleomorphic adenomas and one each of salivary duct carcinoma and liposarcoma and chordoma. Four of the six tumors were diagnosed as benign preoperatively. Prestyloid parapharyngeal space tumors should be indicated for surgery even if they are asymptomatic, because preoperative diagnosis is difficult. It was difficult to deal with tumors that were revealed to be malignant postoperatively. Postoperative adjuvant therapy should be considered case by case by referring to the histology and surgical margin, because malignant parapharyngeal space tumors are heterogeneous. If tumors recur, it is important to follow up strictly to salvage them.