耳下腺のアシン細胞癌と分泌癌の臨床的特徴

Clinical characteristics of acinic cell carcinoma and secretory carcinoma of the parotid gland.

• Tetsuya Terada
• Ryo Kawata
• Keiki Noro
• Masaaki Higashino
• Shuji Nishikawa
• Shin-Ichi Haginomori
• Yoshitaka Kurisu
• Hiroko Kuwabara
• Yoshinobu Hirose

抄録

目的:

耳下腺の乳腺アナログ分泌癌（SC）は，乳癌と同様にETV6-NTRK3融合産物に関連する比較的まれな癌である．当院のこの腫瘍の患者さんを対象に、臨床的特徴と治療成績をレビューしました。

PURPOSE: Mammary analogue secretory carcinoma (SC) of the parotid gland is a relatively uncommon cancer associated with the ETV6-NTRK3 fusion product similar to breast cancer. The clinical characteristics and outcome of treatment were reviewed for patients with this tumor at our hospital.

方法:

本レトロスペクティブ症例シリーズでは、耳下腺のアキン細胞癌（AcCC）と診断された24名の患者を、ETV6-NTRK3融合遺伝子の解析に基づいて、SCまたはAcCCのいずれかに分類した。これら2群を臨床的特徴および画像学的特徴（MRI/US）、細胞学的所見、細針吸引細胞診および凍結切片の精度、治療成績および免疫組織化学的所見について比較した。

METHODS: In this retrospective case series, 24 patients with a diagnosis of acinic cell carcinoma (AcCC) of the parotid gland were classified as having either SC or AcCC based on analysis of the ETV6-NTRK3 fusion gene. These two groups were compared with respect to their clinical and imaging characteristics (MRI/US), cytologic findings, accuracy of fine-needle aspiration cytology and frozen section, treatment outcomes, and immunohistochemical findings.

結果:

ETV6-NTRK3融合遺伝子解析による再分類に基づき、診断は14例がSC、10例がAcCCとなった。SC群は男性患者の割合が有意に高く、AcCC群よりも有意に若かった。画像検査の結果、SCは内部不均一性を示す可能性が有意に高いことが明らかになった。両腫瘍の正確な悪性度判定は細針吸引でも同程度で、その割合はAcCCで60％、SCで50％であった。凍結切片生検による診断では、AcCC群で90％、SC群で93％で正しい悪性度が得られた。

RESULTS: Based on re-classification by ETV6-NTRK3 fusion gene analysis, the diagnosis was SC in 14 patients and AcCC in 10 patients. The SC group had a significantly higher proportion of male patients and was also significantly younger than the AcCC group. Imaging studies revealed that SC was significantly more likely to show internal heterogeneity. Correct grading of both tumors was comparable by fine needle aspiration, with the rate being 60% for AcCC and 50% for SC. Diagnosis by frozen section biopsy diagnosis obtained the correct grade in 90% of the AcCC group and 93% of the SC group.

結論:

以前にAcCCと診断された24人の患者において、ETV6-NTRK3融合産物の再解析を行ったところ、14人の患者が実際にSCを発症していたことが判明した。AcCCとSCは生物学的攻撃性と予後の類似性を示しているが、SC患者は男性と若年者である可能性が有意に高かった。

CONCLUSIONS: In 24 patients previously diagnosed with AcCC, re-analysis of the ETV6-NTRK3 fusion product indicated that 14 patients actually had SC. Although AcCC and SC show similarities of their biological aggressiveness and prognosis, patients with SC were significantly more likely to be male and younger.