Reproductive oncology.

The actual incidence of reproductive tract tumors is difficult to ascertain, presumably because a significant percentage of dogs and cats are neutered, particularly in the United States. Data from European countries, where elective neutering is less common, provides insights. Several studies document the relative frequency of reproductive tumors. Larger studies of the more common tumors, e.g., testicular tumors, provide a substantial amount of information on the clinical presentation and response to treatment of dogs, but overall there is less information available on cats. Numerous case reports document the less commonly reported tumors and will be included in the following discussion.