Most canine cutaneous and subcutaneous tumors are benign but it is the lesser cases of malignant masses that keep pet owners and veterinarians on alert.  This is why it is so important to monitor your dog and report the development of any newly discovered lumps and bumps.  Catching a small cancerous growth at the time of treatment results in a better outcome.
At least once a month, you should perform “lump and bump patrol” on your dog or a methodical petting session by slowly sliding your fingers, palm sides down, along you dog’s body, moving from stem to stern while feeling for new lumps and bumps.  Check any previously discovered lumps for changes in size or appearance.  Alert your veterinarian of any new tumors and/or changes in existing ones.  They rely upon your vigilance as some of the lumps and bumps are sure to be missed in the course of a single exam.
Discovering a new growth on your dog doesn’t necessarily mean you should run to your veterinarian right away.  If the new growth in your dog’s skin is the size of a pea or smaller, observe it once a week to assess any change.  If it is growing and/or changing in appearance, it would be best to have it checked out right away.  If there are no changes, it makes good sense to wait until your dog’s next scheduled exam and discuss it with your veterinarian at that time.  You may want to mark the location of the new lump with a ribbon, hair clip or marking pen or clip some hair over the site.  Growths discovered while the dog is lying down in a relaxed position can disappear when the dog is upright and stressed in the exam room.
The most common type of canine tumors are Lipomas.  They are fat (lipid) cells that grow in subcutaneous areas such as the armpits and along the chest and abdomen and occasionally within the chest or abdominal cavity.  Lipomas usually grow in multiples and can have literally hundreds of them.  These tumors are benign and slow-growing with their only issue being purely cosmetic which does not bother the dog.  Are there exceptions to the rule?  You bet!  This fatty tumor deserves more attention if it is steadily growing where it could interfere with mobility such as the armpit; when there is sudden growth and/or change in appearance; if the tumors outgrow their blood supply which can cause infection and drainage from the mass.  Occasionally, a fatty tumor is actually an infiltrative lip sarcoma and not a lipoma.  Your veterinarian will be alerted if the fine needle aspirate cytology (biopsy) reveals fat cells but the tumor itself feels fixed to underlying tissues and should be aggressively surgically removed and/or treated using radiation therapy.
The most common type of canine benign skin tumors are sebaceous adenomas.  These are microscopic structures found just below the skins surface which secrete an oily substance called sebum.  Sebaceous adenomas are no more than ¼” to 1/3” in size, are wart-like in appearance, and occur primarily in middle-aged and older dogs.  Any breed can develop the tumors however, certain breeds like Cocker Spaniels, English Cocker Spaniels, Samoyeds, Siberian Huskies, Alaskan Malamutes, West Highland White Terriers, Cairn Terriers, Dachshunds, Miniature Poodles, Toy Poodles, Shih Tzu, Basset Hounds, Beagles and Kerry Blue Terriers are particularly predisposed.   A vast majority of sebaceous adenomas need no treatment whatsoever but there are exceptions such as recurrent bleeding or it becomes infected; the constant secretion of sebum which rubs off on to anything it touches; they are unsightly with a warty like appearance; if the mass is growing or changing in appearance as it may be a sebaceous carcinoma which is less common.
Lumps and bumps are the brown spots of the canine aging process.  By teaming up with your veterinarian to assess them on a regular basis will insure that they never become a health issue for your favorite companion.