Imaging Features of Adrenal Glands Infiltration by Multicentric Lymphoma in Dogs and Cats

Few case reports describe the imaging features of lymphoma involving the adrenal glands (AGs) in dogs and cats. This retrospective, descriptive, and multicentric study aimed to describe the ultrasound (US), computed tomography (CT), and magnetic resonance imaging (MRI) findings of confirmed lymphomatous AG infiltration in patients with multicentric lymphoma. The inclusion criteria required cytological or histological confirmation of AG lymphoma and at least one imaging study. Eleven patients were included. Abdominal US was available in 10/11 patients (90%), CT in 2/11 patients (18%), and MRI in 1/11 patient (9%). Six patients (6/11, 54%) (5 dogs and 1 cat) had a bilateral involvement of the AGs, whereas the rest (5/11 patients, 54%) (3 dogs and 2 cats) had a unilateral involvement. On US, the findings included unilateral or bilateral enlargement with a preserved shape, hypoechoic and heterogeneous parenchyma, ill-defined or well-defined margins of the AGs, increased echogenicity of the surrounding retroperitoneal fat, and retroperitoneal effusion. On CT, one patient (1/11, 9%) with bilateral involvement showed enlargement of the AGs with multiple hypoattenuating and hypoenhancing nodules, whereas another patient (1/11, 9%) with unilateral involvement showed a hypoattenuating, hypoenhancing nodule in a rounded, heterogeneously enhanced gland. MRI of one patient (1/11, 9%) revealed bilateral enlargement of the AGs with T2W iso/hyperintensity, T1W isointensity, STIR hyperintensity, and strong and heterogeneous enhancement. Detection of these imaging findings on US, CT, and MRI may support the suspicion of adrenal involvement in the case of multicentric lymphoma in both dogs and cats.