European Journal of Radiology 81 (2012) e491–e494 Contents lists available at ScienceDirect European Journal of Radiology jo ur n al hom epage: www.elsevier.com/locate/ejrad Hepatic lipomas and steatosis: An association beyond chance Gregorio Martin-Benitez a,∗ , Luis Marti-Bonmati b,1 , Carmen Barber a,2 , Rocio Vila a,3 a Department of Radiology, Dr Peset University Hospital, Avda Gaspar Aguilar 90, 46017 Valencia, Spain b Department of Radiology, La Fe University and Polytechnic Hospital, Bulevar Sur s/n 46026 Valencia, Spain a r t i c l e i n f o Article history: Received 26 March 2011 Received in revised form 29 May 2011 Accepted 1 June 2011 Keywords: Lipomas Steatosis Insuline resistance MR Chemical shift a b s t r a c t Objective: To determine if hepatic lipomas have a higher prevalence of liver steatosis than other benign hepatic lesions. Materials and methods: Ninety-two benign hepatic lesions were analyzed with magnetic resonance (MR) imaging. There were 6 lipomas and 86 benign non-lipomatous lesions, including 55 hemangiomas, 23 focal nodular hyperplasias (FNH) and 8 adenomas. All studies included a chemical shift T1-weighted sequence (in-phase and opposed-phase) in order to evaluate the presence of steatosis. Results: A statistically significant relationship (Fischer’s Exact Test, p = 0.019) between hepatic lipomas and steatosis was demonstrated. Fifty percent of hepatic lipomas associated steatosis, while this association was present in only 9% of the non-lipomatous lesions. Conclusion: Lipomas have a significantly greater association with steatosis when compared to nonlipo- matous lesions. This relationship may be related to a common insuline resistance mechanism. © 2011 Elsevier Ireland Ltd. All rights reserved. 1. Introduction Hepatic lipomas are uncommon tumors, usually asymptomatic regardless of their size, which range from a few millimeters to several centimeters in diameter. They are usually encountered as incidental findings on ultrasound (US), computed tomography (CT) or magnetic resonance (MR) imaging. Histologically, these lesions consist of mature adipose tissue and have no risk of malignant degeneration [1–4]. Hepatic steatosis represents the excessive accumulation of triglycerides within the hepatocytes, a phenomenon that may affect the hepatic parenchyma either focally or diffusely. Fatty liver dis- ease covers a severity spectrum ranging from non-inflammatory fatty liver to steatohepatitis with inflammation and cirrhosis. Up to 20% of non-alcoholic steatohepatitis progresses to cirrhosis over 5–7 years [5]. Non-alcoholic fatty liver disease, the most common type, is strongly associated with obesity, type 2 diabetes mellitus and dyslipidemia [6]. On US, lipomas are homogeneous, highly echogenic and well- demarcated masses with round borders and posterior sound attenuation [7]. On CT, lipomas are homogenously hypoattenuat- ing lesions with attenuation values lower than -20 HU. After iodine ∗ Corresponding author. Tel.: +34 639 655 779; fax: +34 961 622 534. E-mail addresses: gregojb@hotmail.com (G. Martin-Benitez), luis.marti@uv.es (L. Marti-Bonmati), carmenbh@terra.es (C. Barber), vilamiralles.ro@gmail.com (R. Vila). 1 Tel.: +34 607 873 154. 2 Tel.: +34 649 143 370. 3 Tel.: +34 676 456 779. contrast material injection, lipomas enhance poorly. When evident, partial lesion enhancement should suggest an angiomyolipoma [8] or a liposarcoma. Although US and CT are able to diagnose hepatic lipomas, MR imaging is highly accurate and reliable in this setting, enabling to evaluate lipomas and steatosis in a single stop-shop study. Dedi- cated chemical shift images obtained with MR dual echo (in-phase and opposed-phase) T1-weighted gradient echo sequences are easily implemented in all MR equipments. Liver microscopic intra- cellular fatty infiltration is defined as decreased signal intensity of the hepatic parenchyma on the opposed-phase images com- pared with the in-phase signal intensity. On the other hand, the macroscopic fat of lipomas is seen as high-signal intensity lesion on the in-phase images with a hypointense peripheral rim (due to phase cancellation artifact) on the opposed-phase. When spec- tral fat suppression pulses are used, signal decay of the lipomas is clearly demonstrated [9]. Searching in our educational data base, we observed that some hepatic lipomas evaluated with MR imaging showed coexistent liver steatosis. The purpose of our study is to test the hypothesis that hepatic lipomas and steatosis are frequently associated with a significant association. If the relationship exists, an alteration in the lipid metabolism secondary to insulin resistance may be a common underlying cause. 2. Materials and methods 2.1. Patients From our teaching files collection, 104 patients with benign hepatic lesions were retrospectively analyzed from July 2004 to 0720-048X/$ – see front matter © 2011 Elsevier Ireland Ltd. All rights reserved. doi:10.1016/j.ejrad.2011.06.018