乳腺小葉癌的細針吸取細胞學

Fine-Needle Aspiration Cytology of Mammary Lobular Carcinoma

很多乳腺癌經細針吸取細胞活檢(FNAB)診斷後已可直接行根治術,在眾多類型的乳腺癌中,小葉癌的誤診率最高,假陰性高達50-70%,且有25%的小葉癌誤為導管癌。本文總結本院5例經手術證實小葉癌FNAB材料,5例中4例FNAB考慮為小葉癌,1例診為導管癌,5例中3例細胞細小,細胞大小較一致,異型性不明顯-部分細胞漿内可見黏液空泡。本型小葉癌FNA細胞學上判斷為惡性的根據是腫瘤細胞的聚合力差,細胞單一,背璟無肌上皮細胞,細胞小而胞漿内有黏液空泡則為小葉癌最典型的特徴。道3例FNAB均考慮為小葉癌,有兩例細胞,胞核均明顯增大,細胞黏合力差,細胞學肯定為惡性。其中一例胞漿内黏液空泡較多見,FNAB及組織病理學均診為印戒細胞型小葉癌。另一例手術後組織病理學證實為多形性小葉癌,但FNAB時未注意到胞漿中偶然見到的空泡-FNAB誤診為導管癌,本文對小葉癌細針吸取細胞學的誤診原因進行了簡單的討論。

High degree of diagnostic accuracy allows definitive operation performing on the basis of a fine needle aspiration cytology(FNAC)diagnosis in many type of mammary carcinoma.However among the com mon breast carcinomas,lobular carcinoma has the highest false-negative rate(50~70%).As many as 25%lobular carcinoma has been misclassified as ductal carcinoma.Among the 93 consecutive cases of breast carcinoma initially diagnosed by FNAC and confirmed by histopathology,5 lobular carcinomas were identified.Morphologic studies were carried out on this 5 cases.Four of these five cases were diagnosed or suggestive as lobular carcinoma by FNAC.One case was misclassified as ductal carcinoma.Cytologically,three of five cases showed small,uniform sized tumor cells that had small nuclei and lacked nuclear atypia.Intracytoplasmic mucinous vacuoles were noted in some tumor cells.The cytology base for malignancy of this type of lobular carcinoma is noncohesiveness of tumor cells,monomorphic population of tumor cells and lacking myoepithelial cells in the background.Small tumor cells with intracytoplasmic mucinous vacuoles are the most characteristic feature of lobular carcinoma.These three cases were correctly con side red as lobular carcinoma by FNAC.Two of five cases showed noncohesive tumor cells with marked enlarged nuclei.Cytology was conclusive for malignancy.Numerous large intracytoplasmic vacuoles were found in one case.For this case,both FNAC and histopathology were diagnosed as signet-ring cell carcinoma-a variant of lobular carcinoma.In the last case,the rare cytoplasmic vacuoles were overlooked and had been misclassified as ductal carcinoma,but histopathology showed that it was a pleomorphic lobular carcinoma.The pitfail in FNAC diagnosis of lobular carcinoma was discussed.