Increased mast cell density in benign and malignant salivary gland tumors

Mast cells are one of the characteristic factors in angiogenesis, growth, and metastatic spread of tumors. The distribution and significance of mast cells in many tumors have been demonstrated. However, few studies evaluated mast cell infiltration in salivary gland tumors. In this study, we have examined mast cell count in benign and malignant salivary gland tumors. A descriptive and cross-sectional study was enrolled on 30 cases of pleomorphic adenoma, 13 cases of adenoid cystic carcinoma, 7 cases of mucoepidermoid carcinoma (diagnosed on the basis of 2005 WHO classification), with adequate stroma in peritumoral and intratumoral areas, and 10 cases of normal salivary glands. The samples were stained with 5% diluted Giemsa solution and the average of stained cells was calculated in 10 random microscopic fields in peri- and intratumoral areas. These data has been analyzed by T-Test, Mann- Whitney and Krusskal- Wallis tests. The average of mast cell count increased in the tumors rather than normal salivary glands. There was no significant difference between benign and malignant tumors, also between different malignant tumors. Infiltration was significantly more in peritumoral stroma in both tumoral groups (PV=0.001). Minor salivary glands contained significantly greater number of mast cells. Although mast cell count increased in benign and malignant salivary gland tumors, but there was not any significant difference between the tumoral groups. We suggested further studies to determine the type of these cells which might be helpful in assessment of biological nature of the tumor and its future treatment modality.