A case of dedifferentiated carcinoma occurring in adenoid cystic carcinoma of the submandibular gland with multiple metastasis

Abstract Dedifferentiated adenoid cystic carcinoma (ACC) are rare variant of ACC characterized histologically by two components: conventional low-grade ACC and high-grade “dedifferentiated” carcinoma. We report a case of dedifferentiated carcinoma occurring in ACC of the submandibular gland with multiple distant metastasis. The patient, a 39-year-old woman was referred to our hospital because of submandibular gland carcinoma with multiple distant metastasis. We underwent a right neck dissection and right submandibular gland tumor resection. Histologically, the low-grade ACC merged gradually into an extensive dedifferentiated component that was composed of solid sheets and cords of anaplastic tumor cells with focal gland formation, and distant metastasis contained dedifferentiated component. We planned the treatment of postoperative radiotherapy and chemotherapy. But the patient is a Chinese living in Japan, so she wish to receive the treatment of post-operative in China and she returned to China.