Liver metastasis with apparent intratumoral superparamagnetic iron oxide uptake

Abstract

Sir, A 70-year-old man with a history of rectal carcinoma was admitted for evaluation of a liver mass. On magnetic resonance (MR) imaging, ferucarbotran-enhanced T2*-weighted images showed a demarcated, lobulated, and hyperintense mass with several linear hypointense structures continuing from the edge of the tumor (Fig. 1). Furthermore, two characteristic zones encircling the mass were detected. The first zone was described as a hypointense margin on ferucarbotran-enhanced T2*-, T2-, and T1weighted images (Figs. 1 and 2). The second zone, which was located outside the first zone, was also described as a linear rim showing hypointense on ferucarbotran-enhanced T2*and T2-weighted images (Fig. 1) and hyperintense on a ferucarbotran-enhanced T1-weighted image (Fig. 2). The mass was histologically confirmed to be metastatic adenocarcinoma. On macroscopic view, many notches were detected from the edge of the tumor. The presence of normal hepatic tissue with a linear shape was microscopically confirmed between tumor tissues on hematoxylin and eosin staining (Fig. 3). The immunohistochemical staining of CD68 showed multiple Kupffer cells at the area corresponding to the residual normal hepatic tissue. The density of Kupffer cells in this area was also increased. The first zone encircling the mass seen on ferucarbotran-enhanced MR images represented the compressed normal hepatic tissue, where the density of Kupffer cells was elevated. In the second zone, the number of red blood cells was significantly increased, suggesting sinusoidal congestion. Superparamagnetic iron oxide (SPIO) can increase tumor-to-liver contrast, based on the fact that the majority of hepatic tumors lack a K. Tsushima . A. Nishie (*) . K. Yoshimitsu . H. Honda Department of Clinical Radiology, Graduate School of Medical Sciences, Kyushu University, 3-1-1, Maidashi, Higashi-ku, Fukuoka, 812-8582, Japan e-mail: anishie@radiol.med. kyushu-u.ac.jp Tel.: +81-92-6425695 Fax: +81-92-6425708