Stivalet Aude, Luciani Alain, Pigneur Frederic, Dao Thu Ha, Beaussart Pauline, Merabet Zahira, Perlbarg Julie, Meyblum Evelyne, Baranes Laurence, Calitchi Elie, Lepage Christophe, Belkacemi Yazid, Lagrange Jean-Leon, Lantieri Laurent, Rahmouni Alain
AP-HP, Groupe Henri Mondor Albert Chenevier, Imagerie Medicale, Creteil, France.
Acta Radiol. 2012 May 1;53(4):367-75. doi: 10.1258/ar.2012.110477.
Invasive lobular carcinoma (ILC) is more often multifocal and bilateral than invasive ductal carcinoma. MRI is usually recommended for detection of all ILC sites. The performance of known diagnostic breast MRI criteria for ILC characterization has not been evaluated to date using bilateral mastectomy specimens as gold standard.
To determine the value of BI-RADS 2006 MRI criteria for ILC detection and characterization, using pathological examination of bilateral mastectomy specimens as the reference standard.
Between 2004 and 2007, we retrospectively included all patients with pathologically documented ILC referred to our institution for bilateral mastectomy and preoperative bilateral breast MRI. The location, diameter, and characteristics (BI-RADS) of all lesions were compared with pathological findings. The sensitivity and positive predictive value of bilateral breast MRI for the diagnosis of ILC were calculated. Association of MRI BI-RADS categorical variables and characterization of ILC were assessed (Fisher exact test).
Among 360 patients treated for ILC in 2004-2007, 15 patients qualified for this study. Thirty-one ILC foci were found on pathological examination (30 ipsilateral and 1 contralateral tumor; mean diameter 23 mm; range 2-60 mm) and all were identified on MRI, with 90% of masses and 10% non-mass-like enhancements; MRI features significantly associated with ILC included absence of smooth margins (P = 0.02) and rim-shaped enhancement (P = 0.039). Enhancement kinetics of the 31 foci were evenly distributed among wash-out, plateau, and persistent profiles. Eleven additional lesions were seen on MRI, mainly corresponding to fibrocystic disease; 91% presented as masses and 9% had a wash-out profile.
Based on the 2006 BI-RADS criteria, breast MRI shows a high sensitivity for ILC detection, at the expense of a 26% false-positive rate, suggesting that a pathological proof by US- or MR-guided biopsy is required in case of suspicious MRI images in this context.
与浸润性导管癌相比，浸润性小叶癌（ILC）更常呈多灶性和双侧性。通常建议采用MRI来检测所有ILC病灶。迄今为止，尚未以双侧乳腺切除标本作为金标准，对已知的用于ILC特征性诊断的乳腺MRI标准的性能进行评估。
以双侧乳腺切除标本的病理检查作为参考标准，确定BI-RADS 2006 MRI标准对ILC检测和特征性诊断的价值。
2004年至2007年期间，我们回顾性纳入了所有因病理确诊为ILC而转诊至我院接受双侧乳腺切除及术前双侧乳腺MRI检查的患者。将所有病灶的位置、直径和特征（BI-RADS）与病理结果进行比较。计算双侧乳腺MRI对ILC诊断的敏感性和阳性预测值。评估MRI的BI-RADS分类变量与ILC特征之间的相关性（Fisher精确检验）。
在2004年至2007年接受ILC治疗的360例患者中，15例符合本研究条件。病理检查发现31个ILC病灶（30个同侧肿瘤和1个对侧肿瘤；平均直径23mm；范围2-60mm），所有病灶在MRI上均被识别，其中90%为肿块，10%为非肿块样强化；与ILC显著相关的MRI特征包括边缘不光整（P=0.02）和环形强化（P=0.039）。31个病灶的强化动力学在廓清型、平台型和持续型之间均匀分布。MRI上还发现了另外11个病灶，主要对应于纤维囊性疾病；91%表现为肿块，9%呈廓清型。
基于2006年BI-RADS标准，乳腺MRI对ILC检测具有较高的敏感性，但假阳性率为26%，这表明在此情况下，若MRI图像可疑，则需要通过超声或磁共振引导下活检进行病理证实。
