Computed tomographic findings in dogs with ovarian tumors: a tortuous ovarian artery consistently identifies ovarian origin in complex abdominal masses

The aim of this retrospective multicentric case series is to describe the CT findings of ovarian neoplasia in dogs. Twenty dogs with pre- and postcontrast CT exam and cytological/histological diagnosis of ovarian neoplasia were included. Five dogs presented with bilateral tumors, for a total of 25 neoplasms: 15 carcinomas (4 bilateral), 4 granulosa cell tumors, 2 poorly differentiated malignant neoplasia (bilateral), 2 luteomas, 1 teratoma, 1 dysgerminoma. In two dogs the tumor developed from an ovarian remnant. Ovarian tumors showed variable size, lobulated shape and pre-contrast heterogenous appearance. Mineral foci and/or fat component were rare, observed in teratoma, granulosa cell tumors (2) and in an ovarian carcinoma. Tumor type was not found to be associated with any CT features. Larger masses were more likely located in the central abdomen ventral to the ipsilateral kidney, to show signs of tumor rupture, and to be associated with abdominal or sternal lymphadenopathy and peritoneal effusion. A tortuous ovarian artery was constantly detectable, associated with an enlarged gonadal vein (12 cases). Related cavitary changes were peritoneal effusion (14 dogs) and sternal lymphadenopathy (7 dogs). Presumed or confirmed metastasis were reported in 9/20 cases, with CT evidence of transcoelomic (serosal thickening, peritoneal nodules, omental cake, implant lesions to the liver, spleen, and diaphragm), lymphatic and hematogenous spread (lungs, liver, bone, muscles, spleen). In conclusion, the present study reports the CT features of different canine ovarian neoplasia. A tortuous ovarian artery may be useful to consistently recognize the ovarian origin of a large abdominal mass.