頸部呈胸腺樣分化上皮細胞癌是一種罕見，發生於甲狀腺或是頸部軟組織的惡性腫瘤。它可以藉由組織病理切片以及免疫生化染色確診。主要的治療方式為手術切除。它被認為是一種對放射線敏感的腫瘤，然而，放射線治療的角色卻仍不明確。我們提出一個頸部呈胸腺樣分化上皮細胞癌的病例，其原發部位為頸部軟組織，一開始接受外科治療，然而手術邊緣在病理切片下難以判定。於追蹤時之電腦斷層發現疑似殘餘腫瘤之情形，因此接受化學及放射線治療。至 2010 年 12 月最後一次門診追蹤的期間，也就是診斷後 47 個月，都沒有局部復發及遠端轉移的情況發生。

Carcinoma showing thymus-like differentiation (CASTLE) is a rare malignant
tumor occurring in the thyroid gland or in the soft tissue of the neck. A definitive diagnosis can be made through histolopathologic examination and immunohistochemical profile. The main treatment modality is surgical excision. It is considered a radiosensitive tumor, however, the role of radiotherapy is uncertain. This is a report on a case of CASTLE of the neck treated with surgery but without adequate margin. A residual
tumor was suspected on computed tomogram scan during follow-up, so sequential chemotherapy and radiotherapy were given. No local recurrence or distant metastasis was found 47 months after initial diagnosis.