颅内孤立性纤维瘤：T2WI之“阴阳”表现
The Yin and Yang of Solitary Fibrous Tumor
An axial T2-weighted magnetic resonance image (top left) reveals a mixed hypo- and hyperintense extraaxial dura-based tumor exerting mass effect on the adjacent right temporal lobe, and a corresponding photomicrograph (original magnifcation, ×40; hematoxylin-eosin stain) (top right) shows dense spindle cell proliferation separated by collagen strips. The yin-yang concept (bottom right) is suggested by lesions with hypocellular (hypointense) and hypercellular (hyperintense) areas.
Medical illustration by Aletta Ann Frazier, MD, American Institute for Radiologic Pathology, Silver Spring, Maryland, and University of Maryland School of Medicine, Baltimore, Maryland (afrazier@acr.org)
孤立性纤维瘤之“阴与阳”
左上图：颅脑MR轴位T2WI示右侧脑外硬脑膜肿瘤呈高低混杂信号，有占位效应，右颞叶受压；
右上图：镜下（HE×40）示密集的梭形细胞增生，被条带状的胶原纤维分隔；
右下图：所谓“阴阳”概念，指病变由富细胞区及少细胞区组成，前者在T2WI上呈高信号，后者呈低信号。
T2WI：左额部脑外肿瘤，信号不均，内见混杂的较高或略低信号区，另见较多低信号的流空血管影。（来源链接：男33岁，右侧肢体进行性无力）
轴位T2WI：小脑幕脑外肿瘤，信号不均，以略低信号为主，可见小囊变区。（来源链接：硬脑膜孤立性纤维瘤（血管外皮细胞瘤））