目的:胎盘部位滋养细胞肿瘤(PSTT)是一种罕见的妊娠滋养细胞肿瘤,以前的影像学报告很少。我们报告了4例PSTT的多参数MRI发现,特别强调了肿瘤背后的“假肌层变薄”。
方法:我们回顾了来自四个机构的4例PSTT的多参数MRI和病理结果。信号强度,增强模式,边距,并评估了肿瘤的位置,在MRI上测量肿瘤下方的子宫肌层厚度和肿瘤对侧的正常子宫肌层厚度。还在切除的标本中测量了肿瘤下方的子宫肌层厚度,并将其与使用Friedman测试在MRI上测量的子宫肌层厚度进行了比较。
结果:所有肿瘤在T1加权成像上都显示出不均匀的信号强度,T2加权成像(T2WI),和弥散加权成像。四个肿瘤中的三个在动态对比增强(DCE)MRI上具有高血管区域。在所有肿瘤中均可见T2WI和DCE-MRI上的低信号边缘。所有肿瘤都不同程度地突出到子宫腔中,并延伸到靠近浆膜的子宫肌层中。在MRI上测量的肿瘤下方的子宫肌层厚度(中位厚度,1.2毫米)明显比病理学上测量的薄(中位厚度,9.5mm)和MRI上与肿瘤对侧的正常子宫肌层厚度(中位厚度,10.3mm)(P=0.02),后两者无显著差异。
结论:MRI上肿瘤下的子宫肌层厚度约为病理学厚度的十分之一。因此,即使在病理上位于浅表子宫肌层内,肿瘤似乎也几乎具有透壁性侵袭。MRI上潜在子宫肌层和低边缘的“假性变薄”可能是由肿瘤对子宫肌层的局灶性压迫引起的,可能是由于胎盘部位子宫肌层的脆性。
OBJECTIVE: Placental site trophoblastic tumor (PSTT) is a rare form of gestational trophoblastic neoplasm with few previous imaging
case reports. We report multiparametric MRI findings in four cases of PSTT with special emphasis on the \"pseudo-myometrial thinning\" underlying the tumor.
METHODS: We reviewed multiparametric MRI and pathologic findings in four cases of PSTT from four institutions. Signal intensity, enhancement pattern, margins, and location of the tumors were evaluated, and myometrial thickness underlying the tumor and normal myometrial thickness contralateral to the tumor were measured on MRI. The myometrial thickness underlying the tumor was also measured in the resected specimen and compared with the myometrial thickness measured on MRI using the Friedman test.
RESULTS: All tumors showed heterogeneous signal intensity on T1-weighted imaging, T2-weighted imaging (T2WI), and diffusion-weighted imaging. Three of the four tumors had a hypervascular area on dynamic contrast-enhanced (DCE) MRI. A hypointense rim on T2WI and DCE-MRI was seen in all tumors. All tumors protruded into the uterine cavity to varying degrees and extended into the myometrium close to the serosa. The myometrial thickness underlying the tumor measured on MRI (median thickness, 1.2 mm) was significantly thinner than that measured on pathology (median thickness, 9.5 mm) and normal myometrial thickness contralateral to the tumor on MRI (median thickness, 10.3 mm) (P = 0.02), and there was no significant difference between the latter two.
CONCLUSIONS: The thickness of the myometrium underlying the tumor on MRI was approximately one tenth of the thickness on pathology. Thus, the tumors appeared to have almost transmural invasion even when pathologically located within the superficial myometrium. This \"pseudo-thinning\" of the underlying myometrium and the hypointense rim on MRI could be caused by focal compression of the myometrium by the tumor, possibly due to the fragility of the myometrium at the placental site.