甲狀腺腫塊常見問題

約有 5-10% 人口甲狀腺會出現結節或腫塊，是常見的疾病。但在單發性結節個案中，兒童約佔 0.22-1.35%， 而成年人佔 4%。單發性甲狀腺結節鑒定的目標，是從眾多甲狀腺問題中分辨出真正的腫瘤。

簡介

甲狀腺結節在任何人口的發病率取決於不同因素，包括性別、年齡、飲食習慣、缺乏碘質的程度、及暴露於環 境性或治療性輻射的機會。甲狀腺結節多發生在女性身上，發病率隨年齡增加，約有 5% 的女仕會於 60 歲出現甲狀腺結節。此外，甲狀腺結節與頭頸位置接受的輻射劑量有直接關係（如二十世紀初治療暗瘡的方法）。

雖然甲狀腺結節於兒童當中較少發病，但 15-20% 的結節有機會演變成惡性腫瘤，風險比成人高得多。大部份的兒童患的甲狀腺結節都屬良性，但相比成人，甲狀腺癌對於兒童較具攻擊性，所以及早作出準確的診斷是很重要的。

初步評估

一個全面的病史（包括頸部腫塊、個人及家族）加上詳細的頭頸部檢驗都是重要的。頸部的疼痛、喘鳴、吞嚥困難等症狀都會增加臨床的懷疑，但不能單靠這些症狀作診斷。 只靠頸部外觀的異樣也不能準確預測腫瘤為惡性。

近期頸部大小的變化﹑腫塊有否依附或入侵周邊組織﹑及可觸知的淋巴結病變，都意味著惡性的可能。聲帶痳痺並不一定與惡性腫瘤有關，此問題在良性腫瘤的情況也有機會出現。

單發性甲狀腺結節的患者應作常規的甲狀腺功能檢查，但因為甲狀腺癌患者的甲狀腺功能一般是正常的，故這檢查並不會發現其甲狀腺功能有異。在這階段不應以血清甲狀腺球蛋白水平作參考，因為良性腫瘤亦能引致其水平提高。

造影

不同的造影診斷各有優點及缺點。

細針穿刺活檢 (FNAB)

鑑於其準確性、安全性及成本效益，細針穿刺活檢是初步診斷甲狀腺腫塊的首選方法。 此活檢是使用細針（-23G）的門診程序，在超聲波引導下進行較佳。細針穿刺得出的細胞學結果應被清楚分類，如圖所示（表三）。

有一個研究複審了超過 28個系列的細針穿刺活檢，其敏感性（83%）、具體性（92%） 及準確性（95%）都被評為遠高於其他甲狀腺的檢查方式。使用較大的針有機會增加檢驗準確程度，但同時亦會增加血腫及損害周邊結構的風險。

表三　細胞穿刺活檢結果的分類

評估與管理

經過仔細的病史查問、臨床檢查及進行單發性甲狀腺的細針穿刺活檢後，可清楚得出一 個合適的管理計劃，作觀察或手術之用。若患者在細針穿刺活檢中發現是良性病變，則可利用超聲波觀察一段時間。若確診病變為惡性，便需要進行甲狀腺切除手術了。

甲狀腺手術的選擇將另文講解。

表四　不同結節的鑑別診斷

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