Salivary Duct Carcinoma with Unusual Clinical Course of Sialolithiasis

Salivary duct carcinoma is a high-grade malignant tumor that is histologically similar to ductal carcinoma of the breast. It accounts for less than 1-3% of salivary gland tumors and 63-100% of cases arise in the parotid gland. Swelling, pain, facial palsy and mass in the salivary gland are clinical features suggestive of salivary duct carcinoma. CT and MR imaging findings are nonspecific. However, a few reports suggest that ill-defined heterogenous mass containing cal cification observed on CT scans may be useful for diagnosis. Although salivary duct carcino ma can show calcifications on CT images (33-50%), it can be confused with sialolithiasis. The authors report two cases of salivary duct carcinoma, which was complicated with sialolithiasis in the submandibular gland (in a 25-year-old man with recurrent distal submandibular duct stone, and a 50-year-old man with intraglandular stone). It is suggested that unusual cases of sialolithiasis should be carefully examined to exclude the suspicion of malignancy before surgery.�