CASE REPORT: A PRIMARY SPLENICFIBROSARCOMA WITH HEPATIC METASTASIS IN A CAPTIVE KOALA (PHASCOLARCTOS CINEREUS)

摘要

A 11-year-old female Koala showed anorexia, lethargy and weakness. Hematology, blood chemistry and urinalysis were non-specific. Computed tomography (CT) revealed ascites and masses within the abdomen, and the volumes of some masses increased 20% during a 10-week period. At necropsy, there was 115 ml of clear ascites, and visceral lesions were located mainly in the spleen and liver. The spleen was diffusely enlarged by infiltrative white firm neoplastic tissue with irregularly protuberant nodules, of0.2 to 5 cm, that had totally effaced the parenchyma. The liver contained multiple random scattered softer nodules, of 0.2 to 2.0 cm, some of which were protruding. One nodule of < 1 cm was noted on the mesentery. Histologically, the neoplasm was composed of a low cellularity of elongated fusiform cells distributed amongst an abundant collagenous matrix. Tumor cells were stained positive intracytoplasmically for vimentin and negative for a-smooth muscle actin. This fibrosarcoma (FS) likely originated from the spleen, with secondary metastasis to the liver, from which via transcoelomic implantation spread to the diaphragm and mesentery. This is considered a rare report of primary splenic FS in a captive koala.