Ectopic thymic carcinoma in parotid gland: a rare case and review of literature

Thymic carcinoma that occurs outside the anterosuperior mediastinum is rare. To date, only five cases of ectopic thymic carcinoma have been reported in the English-language literature. Here, we report a case of 43-year-old Chinese man who suffering from ectopic thymic carcinoma of the parotid gland. Magnetic resonance imaging (MRI) showed a round soft tissue mass in the parotid gland. After enhancement, it showed the edge of the tumor was rough, with irregular shallow lobes. Histological examination (HE) showed tumor cells were invasive, and partially arranged in a lobulated structure. These characteristics were similar to previous English-language literature reports. Immunohistochemical (IHC) examination showed that tumor cells were positive for CD5, CD117 and p63, which confirms this case is ectopic thymic carcinoma. Postoperatively the patient received combined paclitaxel plus carboplatin chemotherapy. Currently, no evidence of metastasis or recurrence has been found in this patient.