ABSTRACT. We report a liposarcoma at the mesojejunoileum that was widely excised, and then the intrahepatic metastatic liposarcoma was found. The dog was treated by two single-agent chemotherapy separately. The patient was an 8-year-old, male Dachshund, and was referred to our hospital owing to the significant distention of the left abdomen. Neither radiography nor ultrasonography detected the actual association of the tumor with the abdominal viscera before surgery. A large-sized tumor mass that adhered to the mesojejunoileum was explored by laparatomy. Final diagnosis of a pleomorphic liposarcoma was made by the routine histology and further identified by Oil Red O stain. The two single-agent chemotherapy including doxorubicin followed by capecitabine, however, failed to cause remission of the intrahepatic metastatic lesions. The patient died 22 months after operation and the cause of death was supposed to be metastatic liposarcoma. KEY WORDS: chemotherapy, liposarcoma, metastasis.J. Vet. Med. Sci. 70(6): 637-640, 2008 Liposarcomas occurred primarily in appendicular or axial locations, and extracutaneous development of liposarcomas was rare in dogs [1,3,4,10]. Liposarcoma tends to be aggressive, locally invasive and may metastasize to lung, liver, spleen and bone [1,5]. They are locally invasive neoplasms that rarely metastasized, and wide excision is preferred to marginal excision [1]. However, the usefulness of chemotherapy in liposarcomas has rarely evaluated [7]. To our knowledge, liposarcoma developed in the mesojejunoileum has not been reported in veterinary literature.A male Dachshund, eight-year-old, was referred to our hospital owing to enlargement of the abdomen, predominately on the left side. He was obese and weighed 11.6 kg. Two months earlier, both radiography and ultrasonography performed at an animal clinic and presumed a large-sized mass associated with the spleen. The patient had a history of gradual distention of the left abdomen, and the intermittent anorexia, vomiting, difficulty at defecation, and occasional listlessness. There was a palpable firmness and painless mass within the abdomen.Lateral radiographs displayed that the mass was within ventrally cranial to middle abdomen, dorsal displacement of stomach and intestines, and caudal displacement of intestines. The ventrodorsal radiograph showed that this mass was located within the left abdomen, and superimposed on the left kidney, and that caused cranial displacement of stomach and medial displacement of intestines (Fig. 1). Distant metastatic lesions were not found by thoracic radiographs. Ultrasonography (USG) revealed that this tumor mass had a feature of a mixed echogenicity, which was within the left abdomen and located caudal to the liver and in front of urinary bladder, and enlarged regional lymph nodes were not found. The mass was measured as 12-cm in maximum diameter.Routinely hematological examination revealed a moderate normocytic, normochromic anemia (hematocrit, 22.5% and hemoglobin, 7.2 g m/dL) with two nucleated RBC i...