Fatty Tumors in Dogs
The discovery of a fatty tumor underneath your pet’s skin can be disconcerting to any pet owner. Luckily, the most common fatty tumors, lipomas, are benign and usually not cause for concern.
“Lipomas are common tumors of dogs, and although the gross appearance and texture of these tumors is characteristic, they are benign tumors in most cases,” said Dr. Rita Ho, veterinary intern instructor at the Texas A&M College of Veterinary Medicine & Biomedical Sciences.
Most lipomas feel fairly soft and movable under the skin and do not usually typically make pets uncomfortable unless they are in a location where normal movement is disrupted. Once your pet develops a lipoma, it is common for additional tumors to appear. If this does occur, each tumor should be checked individually.
“Dogs can form lipomas under any conditions, even if the dog is in good body condition,” said Dr. Ho. “It is not related to any known cause or environmental factor.”
Once diagnosed by a veterinarian, most lipomas do not require treatment unless the location or mass causes any inconvenience for the animal, such as located in an area that restricts any movement or causes discomfort. “In that case, we would recommend surgical excision,” said Dr. Ho. Performing surgery for cosmetic reasons alone is typically not condoned.
Another sub-classification of lipomas, infiltrative lipomas, are also benign but can infiltrate locally into muscle tissue and may need to be removed in some cases. “These tumors are diagnosed by histopathology, which means you can’t just look at the lipoma and call it infiltrating lipoma,” said Dr. Ho. “We need advanced imaging and surgery to help us diagnose this uncommon tumor.”
If, after diagnostic tests are run, it is discovered to be a liposarcoma, however, more immediate attention and action will be necessary. Unlike lipomas and infiltrative lipomas, these rare, fatty tumors are malignant and can spread to the animal’s lungs, bones, and other organs.
“Liposarcomas can be diagnosed through either cytology or histopathology,” said Dr. Ho. “It really depends on the biological behavior of the tumor, and most of time they can be asymptomatic.”
Since liposarcomas are malignant, and potentially can spread to other parts of the body, treatment varies greatly from that of benign lipomas.
“Usually, we recommend surgery and/or radiation treatment to control liposarcomas and some infiltrative lipomas,” said Dr. Ho. “However, since these tumors are not as common, it is important to have your veterinarian check the mass out beforehand.”
As with any abnormality, it is always advisable to consult your veterinarian at the first detection of any new lumps or bumps that you discover while giving Fido his daily tummy rub. Lipomas are fairly common, and though malignant liposarcomas and infiltrative lipomas are rare, it always better to be safe than sorry when it comes to our beloved pets.