Imaging Characteristics of Primary Hepatic Leiomyosarcoma in a Dog

A 13-year-old castrated male Shetland sheepdog presented with loss of appetite, jaundice, and lethargy. Abdominal ultrasonography revealed a hypoechoic mass in the midline of the liver relative to the normal liver parenchyma. CT revealed a hepatic mass with low attenuation (28 HU) on precontrast CT and peripheral contrast enhancement in all phases: arterial phase (93 HU), portal phase (102 HU), and delayed phase (86 HU). The mass size was 4.6 × 3.2 × 3.4 cm. Postmortem MRI findings showed that the hepatic mass had low and high signal intensities on T1 and T2-weighted images, respectively. Histopathological assessment revealed leiomyosarcoma based on morphological and immunohistochemical findings. No tumors other than those in the liver were found; therefore, a diagnosis of primary hepatic leiomyosarcoma was made.