Choroid plexus carcinoma in a goat.

A 15-year-old female goat suddenly developed right-sided head tilting with anorexia and depression. Post-mortem examination of the brain revealed a large, unilateral, well-demarcated, intraventricular neoplasm which was diagnosed as a choroid plexus carcinoma. The neoplasm, which occupied about 75% of the left lateral ventricle, led to unilateral obstructive hydrocephalus and invaded the white and grey matter of the left piriform lobe, with focal subarachnoid spread and meningeal implantation. Histopathological examination revealed loss of branching papillary architecture, invasive growth, a high mitotic index and marked necrosis in the undifferentiated areas of the tumour. Neoplastic cells expressed vimentin and, multifocally, broad spectrum cytokeratins, but were negative for GFAP, NSE and Sl00 antigen. This is the first report of a choroid plexus carcinoma in a goat.