Coenurus cerebralis cysts in the left lateral cerebral ventricle of a ewe.

A three-and-a-half year-old female Rahmani ewe was presented suffering from nervous symptoms. Grossly, a large cyst measuring 7 × 4 cm and weighing 145 g occupied the dilated left lateral ventricle. The overlying cerebral tissue was thin, atrophied and congested. It tore easily, and the cyst was evacuated spontaneously. Microscopically, liquefactive necrosis surrounded by aggregations of macrophages, eosinophils, lymphocytes, fibroblasts and giant cells was predominantly observed. Hyperplasia and severe necrosis of the ependymal cell lining of the lateral ventricle were observed. Extensive subependymal inflammatory cell infiltrations, accompanied by neovascularization and fibroblastic proliferation, were seen. Based on the gross and histopathological lesions and cyst morphology and location, the cyst was diagnosed as Coenurus cerebralis. This report describes a rare case of coenurus cyst in the left lateral cerebral ventricle of a ewe and the associated lesion.