The purpose of this study is to determine if freezing fatty tumors (lipomas) will cause them to shrink and die. Cryoablation is a common freezing technique to kill cells and tumors. We are seeking to determine whether this minimally invasive method of freezing tumors would be a good alternative to surgical removal. The procedure will involve an enhanced device that has been previously tested in dogs with tumors under the skin and in the mammary gland.Dogs of any breed or sex, and aged 6 years or younger, are eligible to participate. Dog owners must have a relationship with a veterinary hospital in the Baltimore-DC region and are currently vaccinated for rabies. Inclusion criteria include:at least one fatty tumor (lipoma) no larger than a golf ball on the trunk of the body patients in good health with no underlying heart, liver, or kidney diseasepatients without chronic skin conditions or diabetes no prior treatments such as chemotherapy, radiation therapy, or immunotherapy for other cancersthe owner has the ability to understand and to sign a written informed consent document and is willing to comply with the study protocol, and has the ability to transport their pet to CIGAT at Johns Hopkins in Baltimore, MD for up to 3 visits the owner is willing to provide follow-up information for a minimum of one year following treatmentIf accepted into the study, the pet owner will also be financially responsible for pre-anesthesia bloodwork at their own veterinarian. It is also recommended that pets over three years of age obtain chest X-rays prior to anesthesia. The cost for cryotherapy and a follow-up exam are funded by the study. Your dog's veterinary medical records with your regular veterinarian will be reviewed to determine eligibility for inclusion. We may also speak with you and ask for pictures of your dog's mass. Your dog will then be examined at the Center for Image-Guided Animal Therapy (CIGAT) at Johns Hopkins in Baltimore, MD. A fine needle aspirate may be taken of the mass to determine the type of mass. If the mass appears to be a lipoma, you will then be asked to perform bloodwork (with X-rays of the chest highly suggested) as part of the pre-anesthetic examination at your regular veterinarian. The bloodwork and X-rays are not covered in the clinical trial. Within 2 weeks, your dog's fatty mass will be treated by freezing (called cryoablation) at CIGAT. There is no charge for this treatment. Your dog's response to treatment will be followed by telephone and email interviews for up to one year.