A ten-year old intact female Chihuahua dog was referred for evaluation of abdominal distension and cough. On presentation, mild difficulty in breathing was noted and abdominal mass was palpated. Radiographic and computed tomography findings were of pleural effusions, ascites and abdominal mass in the left caudal region of abdomen. Malignant ovarian or uterine tumor was suspected. Further diagnostic tests and surgical intervention were suggested, but were declined by the owner. Palliative chemotherapy with carboplatin was well-tolerated in this dog. No other abnormalities except abdominal discomfort, panting and pollakiuria were seen. The dog received 13 times of chemotherapy (every 4 to 6 weeks) during 431 days. At necropsy, significantly enlarged right ovary along with sternal lymph node enlargement was found. The histopathological examination of the ovarian mass revealed cords of mitotically active round or polygonal cells, and a diagnosis of ovarian dysgerminoma was made.

Key words: Chemotherapy, Dog, Dysgerminoma, Pleural effusion, Pseudo-Meigs’ syndrome