Computed tomography may detect liver infiltration of canine diffuse hepatic lymphoma

BACKGROUND: In dogs, hepatic lymphoma is characterized by neoplastic lymphocyte infiltration into the liver. Reports on the computed tomography (CT) findings of the liver for canine hepatic lymphoma are few, with only one study of multiple liver lesions type. OBJECTIVES: The purpose of this study was to retrospectively assess the CT findings of the liver in canine diffuse hepatic lymphoma. METHODS: As control, five dogs without abnormalities in the liver were included. CT data were analysed, and the following were noted: presence of edge bluntness of the liver, presence of periportal collar sign, the liver size:body weight (BW) ratio and the mean attenuation of liver lesions on pre‐contrast, arterial‐phase, portal‐phase and equilibrium‐phase post‐contrast images. RESULTS: On CT examination, edge bluntness of the liver was significantly detected in lymphoma (4/5, 80%), as opposed to the control (0/5, 0%) (p = 0.048, φ = 0.82). The periportal collar sign was detected in lymphoma (3/5, 60%), as opposed to the control (0/5, 0%) (p = 0.17, φ = 0.65). The liver size:BW ratio of lymphoma cases was significantly higher compared to that of the control cases (p = 0.0002, r = 0.92). The mean Hounsfield unit of lymphoma cases in the pre‐contrast, arterial‐phase, portal‐phase and equilibrium‐phase images were significantly lower than in the control cases (p = 0.005, r = 0.81; p = 0.0003, r = 0.91; p = 0.01, r = 0.75 and p = 0.02, r = 0.71, respectively). CONCLUSIONS: Hepatic lymphoma should be a differential for a blunted and enlarged liver with hypoattenuation on CT examination.