顎下腺腫瘍における細胞診の信頼性と術式選択

The treatment of choice of tumors arising from the submandibular gland as assessed by fine needle aspiration biopsy

Ⅰ．はじめに

　顎下腺腫瘍は耳下腺腫瘍よりも発生頻度は低いが，全体に占める悪性腫瘍の割合が高く，その予後も悪いとされている^1）。したがって，顎下腺腫瘍における術前の良・悪性の診断には注意を要すると考えられる。

　当科では，顎下腺腫瘍の手術に際して穿刺吸引細胞診（以下，FNAと略す）で良性との結果が得られても，病歴や触診所見，画像診断などで悪性腫瘍が否定できない場合には，顎下部郭清術や所属リンパ節摘出術を行ってきた。しかし顎下部の手術では，顔面神経下顎辺縁枝の麻痺の可能性や整容面での問題から，侵襲の大きい顎下部郭清術を避けたいところである。

　そこで，今回は当院で一次治療を行った顎下腺腫瘍症例の術前FNAに着目し，その結果と最終病理診断の関連性，術式や術後合併症について検討することで術式の選択について考察した。

　In the clinical management of tumors of the submandibular gland,it is important to distinguish between benign and malignant tumors,in order to make indication for neck dissection. As we have identified the indication for neck dissection comprehensively,not only by fine needle aspiration biopsy but also by history taking and CT and/or MRI,we often performed neck dissection for benign tumors,resulting in the high rate of complications. In this retrospective study,we have tried to find out the best way of the judgement.

　Forty-four patients with submandibular tumors, operated on between 1996 and 2007, were investigated retrospectively. Among them, 37 cases were benign and 7 cases were malignant. Mean and standard deviation of the age of these patients were 51.6 and 18.6.

　Analyzing the results of the fine needle aspiration biopsy,35 out of 37 benign tumors were diagnosed correctly as benign tumor,7 out of 7 malignant tumors were diagnosed as malignant tumor,revealing that the results of FNA were much more reliable for suspecting the pathological diagnosis of the tumor arising from the submandibular gland as compared with the series of parotid tumors. We evaluated the tumor comprehensively and decided to perform neck dissection in 16 patients even though the results of FNA were benign. However,the results of this study suggested that if the FNA findings do not show malignancy,neck dissection is not necessary.