Background: Mucoepidermoid carcinoma is the most common malignant salivary gland tumor. The histopathologic grade of this tumor is the most important predictor of prognosis, which has a huge impact on the treatment protocols. Tumor behavior is worse with an aggressive outcome in high-grade than in low-grade mucoepidermoid carcinoma, leading to a need for more intensive treatment.
Patients and methods: A retrospective clinical study and review of histopathologic grading were carried out, using the two most well-known grading systems, of 60 patients with mucoepidermoid carcinoma diagnosed at the Pathology Department, National Cancer Institute, Cairo University, from 2005 to 2010.
Results: The recurrence rate was strongly correlated with high tumor grade according to Armed Forces Institute of Pathology and Brandwein grading systems (P=0.003 and 0.03, respectively). Male sex was significantly correlated with a high tumor grade (P=0.01). Lymph node status was significantly correlated with the overall survival (P=0.026). Using the Brandwein grading system, it was found that as the histologic grade increased from low and intermediate to high, disease-free survival (P=0.029) was significantly decreased.
Conclusion: The outcome of the cases with intermediate-grade mucoepidermoid carcinoma is less clear and may be categorized as low or high grade according to the grading system used. The Brandwein grading system may have a better predictive value than the Armed Forces Institute of Pathology systems as it identifies the low-grade cases very well.