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)
孤立性纖維瘤之「陰與陽」
左上圖：顱腦MR軸位T2WI示右側腦外硬腦膜腫瘤呈高低混雜信號，有佔位效應，右顳葉受壓；
右上圖：鏡下（HE×40）示密集的梭形細胞增生，被條帶狀的膠原纖維分隔；
右下圖：所謂「陰陽」概念，指病變由富細胞區及少細胞區組成，前者在T2WI上呈高信號，後者呈低信號。
T2WI：左額部腦外腫瘤，信號不均，內見混雜的較高或略低信號區，另見較多低信號的流空血管影。
軸位T2WI：小腦幕腦外腫瘤，信號不均，以略低信號為主，可見小囊變區。