Clinicopathologic and Immunohistochemical Analysis of Salivary Duct Carcinoma in Major and Minor Salivary Glands

Objective: To investigate the clinicopathologic characteristics of salivary duct carcinoma (SDC) in major and minor salivary glands and the possible role of MMP (matrix metalloproteinase)- 2 and MMP-9 in SDC. Methods: Clinicopathologic features of 10 SDCs were described. Immunohistochemical expressions of MMP-2 and MMP-9 proteins were examined in the paraffin samples of the 10 SDCs and 10 basal cell adenomas (BCA). The scoring of the immunoreactivity was estimated by integrated optical density (IOD) through a digital image analyser. Results: The patients of SDC presented clinically with a local mass or swelling, frequently painful (6 of the 10 cases). The symptoms of facial paralysis or lip numbness (3/10) and lymph node metastasis (6/10) were usually detected. SDCs showed increased expression in both MMP-2 and MMP-9 proteins as compared with BCAs. Moreover, MMP-2 and MMP-9 proteins were markedly increased in metastatic compared with non-metastatic SDCs. Conclusion: MMP-2 and MMP-9 may play an important role in invasion and metastasis of SDC. Toothache may be an important clinical characteristic of SDC originated in maxillary sinus. SDC histologically showed various proportions of papillary, comedo, cribriform and solid patterns.