Computed tomographic imaging of infiltrative lipoma in 22 dogs

Twenty two dogs with an infiltrative lipoma had computed tomographic (CT) i mages acquired to evaluate the extent of local disease. Ten dogs had underg one at least one cytoreductive surgical procedure (range = 1-3; median = 2) prior to imaging. Twenty dogs had measurable disease on CT images; 2 dogs had diffuse disease at a previous surgical site that could not be measured. Tumor volume (n = 20) ranged from 20 to 5,632 cm(3) (median = 345 cm(3); m ean = 996 cm(3)). None of the dogs had evidence of bone involvement on the CT images; 2 of the 22 dogs had tumors that did not come into direct contac t with osseous structures, All dogs with measurable disease had evidence of a fat opacity mass with variable degrees of muscle infiltration. Eleven of 22 dogs were given intravenous contrast medium prior to image acquisition and there was not evidence of enhancement of the infiltrative lipoma in any dog. Based on CT images, tumors were classified as well-defined in 9 dogs, moderately well-defined in 4, not well-defined in 3 and a mix of well-defi ned and not well-defined in 6 dogs. Tumors tended to be less well-defined i n regions where the infiltrative lipoma interdigitated with normal body fat . It appears CT imaging allows adequate discrimination of tumor with the ca veat that differentiation of normal fat from infiltrative lipoma can be pro blematic.