Abstract
Salivary duct carcinoma (SDC) in the submandibular gland is rare. In the present study, 4 cases of submandibular gland SDC were examined. According to pre-therapy staging, 1 patient had stage I SDC; 2 had Stage II; and 1 had Stage IVa. In preoperative cytology, malignancy was suspected in only 1 patient. In intraoperative rapid diagnosis, SDC was suspected in 1 patient, while the other 3 patients were diagnosed with malignant tumor. Overexpression of HER-2 was observed in 3 patients. Although neck dissection and postoperative irradiation were performed in all patients, these treatments resulted in the occurrence of distant metastasis in 3 patients. Further, 2 patients died due to disease progression. SDC has a poor prognosis even when multidisciplinary treatments are performed. However, because overexpression of HER-2 is frequently observed, new therapies using molecularly targeted drugs such as trastuzumab are expected to be developed.
