Proliferative sparganosis in a cat.

Aberrant, proliferative sparganosis was diagnosed in a 6-yr-old male domestic long-haired cat from Gainesville, Florida. The cat spent all of its life in Florida. Postmortem examination revealed lesions and spargana in the stomach, spleen, and liver. By light and electron microscopy, unusual mononuclear cells, interpreted as host-derived monocytes, were evident in the stroma of the spargana. Retrovirus-like particles were present in the cytoplasm of some of these cells.