Surgically induced tumor seeding in eight dogs and two cats.

Surgically induced tumor seeding was diagnosed in 8 dogs and 2 cats. All animals had histologic confirmation of neoplasia in an unusual location or pattern, and a history of surgical manipulation of a similar histologic-type tumor at the site of seeding. Highly malignant carcinomas (8/10 animals) were the most common tumor type. Seeding occurred secondary to a variety of surgical procedures and in the face of various adjuvant therapies. Seeded tumors were recognized from 2 to 30 weeks after the causal procedure (median, 6 weeks). Survival times after the causal procedure ranged from 15 to 131 weeks (median, 45 weeks) and 8 of 10 animals died or were euthanatized because of seeded tumors.