舌下腺に発生した胸腺様分化を示す癌腫（CASTLE）

Carcinoma Showing Thymus-Like Differentiation (CASTLE) Arising in the Sublingual Gland.

• Laura Ardighieri
• Michele Tomasoni
• Simonetta Battocchio
• Fabio Facchetti
• Roberto Maroldi
• Piero Nicolai
• Davide Lombardi

抄録

胸腺様分化を示す癌腫（CASTLE）は、甲状腺や頸部の軟部組織に発生するまれな腫瘍である。舌下腺に発生したCASTLEの最初の症例を報告する。症例は35歳の健康な男性で、口腔内右前床の粘膜下病変と同側の頸部腫瘤を呈した。この病変は以前に頸部CTおよび超音波ガイド下細針吸引細胞診で調査され、転移性扁平上皮癌と診断されていた。口腔磁気共鳴画像診断、ポジトロン断層撮影、舌下腫瘤の非洗浄細針吸引細胞診を行った結果、原発性腫瘍の摘出と頸部郭清を行い、舌下腺悪性腫瘍の影響を受けていると診断された。形態学的・免疫組織化学的所見から原発性舌下腺CASTLEと診断された。この患者は補助放射線治療を受け、治療後2年で無病となった。病変の病理学的特徴を説明し、考えられる鑑別診断について議論する。

Carcinoma showing thymic-like differentiation (CASTLE) is a rare tumor most commonly occurring in the thyroid and soft tissues of the neck. We report the first case of CASTLE occurring in the sublingual gland. The patient, a 35-year-old healthy man, presented with a submucosal lesion located in the anterior right floor of the oral cavity and an ipsilateral neck mass. The lesion had been previously investigated by neck computed tomography and ultrasound-guided fine needle aspiration cytology and diagnosed as metastatic squamous cell carcinoma. After oral cavity magnetic resonance imaging, positron emission tomography, and a non-diriment, fine needle aspiration cytology of the sublingual mass, the patient was treated as affected by a sublingual gland malignancy with removal of primary tumor and neck dissection. Morphological and immunohistochemical findings were diagnostic for primary sublingual gland CASTLE. The patient received adjuvant radiotherapy and is free of disease 2 years after treatment. We describe the pathological features of the lesion and discuss the possible differential diagnoses.