副耳下腺に発生した未分化癌例

抄録

Undifferentiated carcinoma of the accessory parotid gland is extremely rare. We report the case of an 83-year-old woman with undifferentiated carcinoma of the accessory parotid gland. The patient was referred to our hospital for detailed investigation and treatment of a mass in the left cheek. MRI revealed a solid tumor with an irregular edge in the masseter muscle. The findings of fine-needle aspiration cytology led to suspicion of the tumor being an adenocarcinoma. Therefore, the tumor was surgically resected by a direct approach via a cheek incision. The buccal branch of the facial nerve was present within the tumor, so that it was sacrificed. Histologically, the tumor was diagnosed as an undifferentiated carcinoma. Postoperative radiation therapy was administered, but one year six months after the surgery, the patient was diagnosed as having metastases in the submandibular lymph nodes. We performed dissection of the neck lymph nodes and administered additional postoperative radiation therapy for the submandibular region. The patient has had no recurrence or metastasis in the four years since until now.

There are various surgical approaches for resection of tumors of an accessory parotid gland, and it is necessary to select the most suitable approach after considering the advantages and disadvantages of each approach. Also, undifferentiated carcinoma of the salivary gland has a high recurrence rate and a poor prognosis, and multimodality treatment is important to control postoperative recurrence.