Carcinoma ex pleomorphic adenoma of the submandibular gland: A retrospective analysis of 86 patients

Objectives To evaluate the prognostic and locoregional metastatic features of carcinoma ex pleomorphic adenoma of submandibular gland (SMG-CXPA) and improve the understanding of this uncommon condition. Patients and methods We retrospectively reviewed patients who were diagnosed with SMG-CXPA. The survival data of SMG-CXPA patients were statistically analyzed using Cox regression and Kaplan-Meier method. The associations between cervical metastasis and clinicopathological parameters were evaluated using chi-squared test. Additionally, two different histological categories (histological grade and invasiveness) and their combination were evaluated with the Kaplan-Meier method and receiver operating characteristic curves. Results In total, 86 patients were diagnosed: 38 clinically node-negative, 31 pathologically node-negative, and 17 node-positive patients. Clinical tumor stage and histological grade were two independent prognostic factors for SMG-CXPA. There were significant correlations between sex, tumor size, clinical tumor stage, clinical lymph node stage, histological grade, invasiveness, malignant components, perineural invasion, and no specific criteria exist for the clinical outcome. Conclusion SMG-CXPA is a high-grade malignancy with an unfavorable prognosis. Elective neck dissection should be performed in SMG-CXPA patients with a risk of locoregional metastasis. Histological grade seems to be a more valuable predictor of lymph node involvement than invasiveness.